An exclamation used to startle or frighten. [1913 Webster]
bo, abbr. colloq. body odour.
bo, int. = BOO.
bo, n. US colloq. (as a form of address) pal; old chap.
Etymology:
19th c.: perh. f. BOY
N petitioner, solicitor, applicant, suppliant, supplicant, suitor, candidate, claimant, postulant, aspirant, competitor, bidder, place hunter, pot hunter, prizer, seeker, beggar, mendicant, moocher, panhandler, freeloader, sponger, mumper, sturdy beggar, cadger, hotel runner, runner, steerer, tout, touter, pauper, homeless person, hobo, bum, tramp, bindle stiff, bo, knight of the road (poverty), hippie, flower child, hard core unemployed, welfare client, welfare case, canvasser, bagman, salesman.