Fil"ly (?), n.; pl. Fillies (#). [Cf. Icel. fylia, fr. foli foal. See Foal.]
1. Zool.
A female foal or colt; a young mare. Cf. Colt, Foal.
Neighing in likeness of a filly foal.
Shak.
2.
A lively, spirited young girl.
[Colloq.]
Addison.
© Webster 1913.