debut n.

"target of a joke, object of ridicule," 1610s, from earlier sense "target for shooting practice, turf-covered mound against which an archery target was set," (mid-14c.), from Old French but "aim, goal, end, target" of an arrow, etc. (13c.), which seems to be a fusion of Old French words for "end" (bot) and "aim, goal" (but), both ultimately from Germanic. The latter is from Frankish *but "stump, stock, block," or some other Germanic source (compare Old Norse butr "log of wood"), which would connect it with butt (n.1).

1824, "male performer or speaker making his first public appearance," from French debutant, noun use of present participle of débuter "to make the first strike" (in billiards, etc.), from debut (see debut).

1801, "female stage actress making her first public performance," from fem. of French debutant, noun use of present participle of débuter "to make the first strike" (in billiards, etc.), from debut (see debut). In reference to a young woman making her first appearance in society, from 1817.