Someone who's sexual nature and/or orientation changes. Someone who has more than one mode of sexual nature and/or orientation.
The person's morphasexual nature allowed zim to be straight at some times and gay at other times.
by Ophir September 04, 2005
Someone that is so oversexed that they'll go either way just to get their rocks off, gay or straight.
That boy's nothing but a common morphasexual.
by Ferd Berfel November 03, 2003