1.  obligation(n = noun.act) duty, responsibility - the social force that binds you to the courses of action demanded by that force; "we must instill a sense of duty in our children"; "every right implies a responsibility; every opportunity, an obligation; every possession, a duty"
is a kind of social control
has particulars: job, guardianship, keeping, safekeeping, moral obligation, noblesse oblige, burden of proof, civic duty, civic responsibility, filial duty, imperative, incumbency, legal duty, line of duty, white man's burden, prerequisite, requirement, demand, requirement
Derived forms verb obligate₁, verb oblige₁

2.  obligation(n = noun.state) - the state of being obligated to do or pay something; "he is under an obligation to finish the job"
is a kind of state
has particulars: financial obligation, indebtedness, liability
Derived forms verb obligate₃, verb obligate₂

3.  obligation(n = noun.linkdef) indebtedness - a personal relation in which one is indebted for a service or favor;
is a kind of personal relation, personal relationship
Derived form verb oblige₃

4.  obligation(n = noun.possession) certificate of indebtedness, debt instrument - a written promise to repay a debt;
is a kind of document
has particulars: cash equivalent, cd, certificate of deposit, note, note of hand, promissory note, floater, bond, bond certificate

5.  obligation(n = noun.communication) - a legal agreement specifying a payment or action and the penalty for failure to comply;
is a kind of written agreement
has particulars: debt
Derived forms verb obligate₃, verb oblige₂

1.  The act of obligating. [1913 Webster]

2.  That which obligates or constrains; the binding power of a promise, contract, oath, or vow, or of law; that which constitutes legal or moral duty. [1913 Webster]
"A tender conscience is a stronger obligation than a proson." [1913 Webster]

3.  Any act by which a person becomes bound to do something to or for another, or to forbear something; external duties imposed by law, promise, or contract, by the relations of society, or by courtesy, kindness, etc. [1913 Webster]
"Every man has obligations which belong to his station. Duties extend beyond obligation, and direct the affections, desires, and intentions, as well as the actions." [1913 Webster]

4.  The state of being obligated or bound; the state of being indebted for an act of favor or kindness; -- often used with under to indicate being in that state; as, to place others under obligations to one. [1913 Webster]

5.  A bond with a condition annexed, and a penalty for nonfulfillment. In a larger sense, it is an acknowledgment of a duty to pay a certain sum or do a certain things. [1913 Webster]

obligation, n.
1 the constraining power of a law, precept, duty, contract, etc.
2 a duty; a burdensome task.
3 a binding agreement, esp. one enforceable under legal penalty; a written contract or bond.
4 a a service or benefit (repay an obligation). b indebtedness for this (be under an obligation).

Idiom:
day of obligation Eccl. a day on which all are required to attend Mass or Communion. of obligation obligatory.

Derivative:
obligational adj.

Etymology:
ME f. OF f. L obligatio -onis (as OBLIGE)

N  necessity, involuntariness, instinct, blind impulse, inborn proclivity, innate proclivity, native tendency, natural tendency, natural impulse, predetermination, necessity, necessitation, obligation, compulsion, subjection, stern necessity, hard necessity, dire necessity, imperious necessity, inexorable necessity, iron necessity, adverse necessity, fate, what must be, destiny, destination, fatality, fate, kismet, doom, foredoom, election, predestination, preordination, foreordination, lot fortune, fatalism, inevitableness, spell, star, stars, planet, planets, astral influence, sky, Fates, Parcae, Sisters three, book of fate, God's will, will of Heaven, wheel of Fortune, Ides of March, Hobson's choice, last shift, last resort, dernier ressort, pis aller, necessaries, necessarian, necessitarian, fatalist, automaton, necessary, needful, fated, destined, elect, spellbound compulsory, uncontrollable, inevitable, unavoidable, irresistible, irrevocable, inexorable, avoidless, resistless, involuntary, instinctive, automatic, blind, mechanical, unconscious, unwitting, unthinking, unintentional, impulsive, necessarily, of necessity, of course, ex necessitate rei, needs must, perforce, nolens volens, will he nil he, willy nilly, bon gre mal gre, willing or unwilling, coute que coute, faute de mieux, by stress of, if need be, it cannot be helped, there is no help for, there is no helping it, it will be, it must be, it needs to be, it must be so, it will have its way, the die is cast, jacta est alea, che sara sara, it is written, one's days are numbered, one's fate is sealed, Fata obstant, diis aliter visum, actum me invito factus, non est meus actus, aujord'hui roi demain rien, quisque suos patimur manes, The moving finger writes and having writ moves on, Nor all thy piety nor wit shall draw it back to ca.

N  promise, undertaking, word, troth, plight, pledge, parole, word of honor, vow, oath, profession, assurance, warranty, guarantee, insurance, obligation, contract, stipulation, engagement, preengagement, affiance, betroth, betrothal, betrothment, promising, promissory, votive, under hand and seal, upon oath, promised, affianced, pledged, bound, committed, compromised, in for it, as one's head shall answer for, in for a penny in for a pound, ex voto, gage d'amour.

N  conditions, terms, articles, articles of agreement, memorandum, clauses, provisions, proviso, covenant, stipulation, obligation, ultimatum, sine qua non, casus foederris, conditional, provisional, guarded, fenced, hedged in, conditionally, provisionally, pro re nata, on condition, with a string to it.

N  debt, obligation, liability, indebtment, debit, score, bill, check, account (credit), arrears, deferred payment, deficit, default, insolvency, bad debt, interest, premium, usance, usury, floating debt, floating capital, debtor, debitor, mortgagor, defaulter, borrower, indebted, liable, chargeable, answerable for, in debt, in embarrassed circumstances, in difficulties, incumbered, involved, involved in debt, plunged in debt, deep in debt, over one's head in debt, over head and ears in debt, deeply involved, fast tied up, insolvent, minus, out of pocket, unpaid, unrequited, unrewarded, owing, due, in arrear, outstanding, past due, aes alienum debitorem leve gravius inimicum facit, neither a borrower nor a lender be.

financial obligation, holy day of obligation, moral obligation