Green’s Dictionary of Slang

(US teen) good, excellent, a general term of approbation; often as excl.

1951		(con. 1918) S. Longstreet Pedlocks (1971) 257: The meal was sure neato, sir.
1968		N. Giovanni ‘A Revolutionary Tale’ in King Black Short Story Anthol. (1972) 24: I have this really neato pink IBM.
1978		R. De Christoforo Grease 150: He’s neat-o.
1988		S. King Tommyknockers (1989) 232: But look! Neat-o, huh?
1994		R. Crumb Zap Comix 13 in Coffee Table Art Book (1997) 25: Oboy! Neato! Just what I wanted!
1990		Eble Campus Sl. Apr. 6: neato – interesting, intriguing.
2003		McGill Reed Dict. of N.Z. Sl. 141: neat as/neat, eh?/neato Pleasing. ‘Like my jumper? Neat as, eh?’ Local variants of US ‘neat’, for anything impressive to teens, popular ANZ from later C20.