Involving, relating to, or characterized by a desire to engage in sexual activity with everyone, or with all kinds of people; practising or tolerant of such activity. Also: sexual in all or many ways.
Capitol Hill's other main drag continues to flourish as a home to omnisexual hipsters and the people who love them. (2002 21 March)
Not exactly a slow day at the office, I just noticed the June new words link when I went to look up something else.