patron

both women and men are patrons today, and the word functions fairly inclusively, but it comes from the Latin for "father," it has been used more of men than of women, it is part of the exceedingly non-parallel word pair "matron/patron," and it has some fairly sexist relatives ("patronage," "patronize," "patronymic"). For those reasons, you may want alternatives: benefactor, sponsor, backer, donor, supporter, promoter, philanthropist, booster, champion, partisan, angel, guardian angel, bankroll, advocate, mentor, helper, protector; library user, customer, shopper, buyer, purchaser, subscriber, client. See also matron.