Definitions for jill
Generic use for any female (as Sheila in Australian English), especially paired (since the 15th c., compare Ienken and Iulyan) with the male Jack.
A young woman; a sweetheart; like the variant spelling Gill it was also associated with various assertive uses of the term flirt, as in flirtgigg (used by William Shakespeare for a 'woman of light or loose behavior').
A man's right hand; .
A jillstrap: the female counterpart to a jockstrap.
Origin: By analogy with jack or jackrabbit.
a young woman; a sweetheart. See Gill