stallion(n = noun.animal) entire - uncastrated adult male horse;
is a kind of male horse
has particulars: stud, studhorse

   A male horse not castrated; a male horse kept for breeding. [1913 Webster]

stallion, n. an uncastrated adult male horse, esp. one kept for breeding.

Etymology:
ME f. OF estalon ult. f. a Gmc root rel. to STALL(1)

N  carrier, porter, bearer, tranter, conveyer, cargador, express, expressman, stevedore, coolie, conductor, locomotive, motor, beast, beast of burden, cattle, horse, nag, palfrey, Arab, blood horse, thoroughbred, galloway, charger, courser, racer, hunter, jument, pony, filly, colt, foal, barb, roan, jade, hack, bidet, pad, cob, tit, punch, roadster, goer, racehorse, pack horse, draft horse, cart horse, dray horse, post horse, ketch, Shetland pony, shelty, sheltie, garran, garron, jennet, genet, bayard, mare, stallion, gelding, bronco, broncho, cayuse, creature, critter, cow pony, mustang, Narraganset, waler, stud, Pegasus, Bucephalus, Rocinante, ass, donkey, jackass, mule, hinny, sumpter horse, sumpter mule, burro, cuddy, ladino, reindeer, camel, dromedary, llama, elephant, carrier pigeon, pallet, brace, cart, dolley, support, fork lift, carriage, ship, equine, asinine.

N  man, male, he, him, manhood, gentleman, sir, master, sahib, yeoman, wight, swain, fellow, blade, beau, elf, chap, gaffer, good man, husband, Mr, mister, boy, cock, drake, gander, dog, boar, stag, hart, buck, horse, entire horse, stallion, gibcat, tomcat, he goat, Billy goat, ram, tup, bull, bullock, capon, ox, gelding, steer, stot, androgen, homosexual, gay, queen, male, he-, masculine, manly, virile, unwomanly, unfeminine, Pron, he, him, his, hominem pagina nostra sapit, homo homini aut deus aut lupus, homo vitae commodatus non donatus est.