Green’s Dictionary of Slang

(Aus./US) critical, fault-finding.

1916		Tomahawk (White Earth, Becker Co., MN) 19 Oct. 3/3: Wal, if them tourists ain’t too durned snooky the hoss ’ll be safe in the ’dobe-shack.
1933		F. Clunes Try Anything Once n.p.: There was a snooky guy up in the corner listening to all I had to say.