TOMBOY
tomboy, romp, hoyden
(noun) a girl who behaves in a boyish manner
Source: WordNet® 3.1
Etymology
Noun
tomboy (plural tomboys)
A girl who behaves in a typically boyish manner.
Synonyms: hoyden, ladette, romp
(with regards to behaviour) Antonym: girly girl
(with regards to gender) Antonym: macho man
(with regards to gender and behaviour) Antonym: femboy
(Philippines, colloquial) A lesbian.
Source: Wiktionary
Tom"boy`, n. Etym: [Tom (for Thomas, L. Thomas, fr. Gr. boy.]
Definition: A romping girl; a hoiden. [Colloq.] J. Fletcher.
Source: Webster’s Unabridged Dictionary 1913 Edition