adj: sometimes having sexual attraction and/or feelings, but usually not. generally asexual but perhaps capable of sexual desire under certain conditions, eg love or romance.
noun: person who identifies as graysexual
Whereas sexual orientation exists along a continuum of heterosexual, bisexual and homosexual, sex drive also exists along a continuum. Some people (highly sexual) desire to have sex with anyone they can; some people (strictly asexual) have no sexual desires; graysexuals are predominantly asexual but capable of manifesting sexual desires under specific circumstances. This is not to be confused with an asexual that is satisfying a partner's sexual desires despite lacking sexual desire of their own.
"Dude, are you gay?"
"Nah, I'm graysexual. I can see that there are plenty of hot chicks here, but that doesn't mean I want to have sex with any of them."