1.) To take off all your clothes.
2.)To do something intense or hardcore.
3.)A meaningless word used as an adjective in Dayton, Ohio, often strewn together with other meaningless adjectives.
"Oh wow, full nude, I can't believe you had sex with three girls in one night in your parents bed."
"Tom took off all his clothes; he went full nude."
"Oh shit, oh fuck, ultimate-ultimate, straight penetrate, full nude, big pig, big baby."