Green’s Dictionary of Slang

groovy! excl.

also groovy cool!
[groovy adj.2 (1)]

a general excl. of approval, pleasure.

[US]J. Rechy Numbers (1968) 129: ‘Groovy,’ the guy in the sweatshirt calls out.
[US]E. Bunker No Beast So Fierce 176: ‘We can blow a couple of joints, drive around, and see if we really like each other.’ ‘Groovy.’.
[US]Eble Campus Sl. Mar. 3: groovy cool – fantastic.
[Ire](con. 1970) G. Moxley Danti-Dan in McGuinness Dazzling Dark (1996) I ix: Groovy baby.