butch
A (traditionally) masculine man or woman, and especially a masculine lesbian. Often the "dominant" partner in a lesbian relationship, and especially of a butch/femme lesbian relationship.
Dressing masculinely does not make a woman into a lesbian, contrary to popular belief; it's usually more convenient.
Acting masculinely only means that's the gender role that the person identifies with; it has nothing to do with their sexual life. A highly masculine man could be gay for all we know and a very feminine man could be straight for all we know, and both of these cases are frequent.
Dressing masculinely does not make a woman into a lesbian, contrary to popular belief; it's usually more convenient.
Acting masculinely only means that's the gender role that the person identifies with; it has nothing to do with their sexual life. A highly masculine man could be gay for all we know and a very feminine man could be straight for all we know, and both of these cases are frequent.