abominable snowman, n. — Green’s Dictionary of Slang

abominable snowman n.

[play on his being extremely cool adj. (5)]

(US teen) an admirable male.

1963		Kingsport Times (TN) 24 Nov. 82/2: If a girl scrawls ‘abominable snowman’ [...] that’s a high compliment — he has everything.
1969		Summerfield Sun (KS) 9 Jan. 2/3: Teen Talk Glossary [...] Abominable snowman — A great guy.