A rogue or scoundrel. Some etymologists believe that this term, which originated about 1700, once meant the illegitimate son of a soldier (gun). Others, however, believe it simply was a euphemism for son of a bitch that appealed because of its rhyme. Still another theory, recorded in Smyth’s Sailor’s Word-Book (1867), is that it was originally applied to boys who were born at sea, in the days when women were permitted to accompany their sailor husbands, and alluded to a child being “cradled under the breast of a gun.”