Green’s Dictionary of Slang

(Aus.) a superior person or thing.

1905		Duke Tritton’s Letter n.p.: I’m teaching Mary and all the Tin Lids in the district to Dark An’ Dim, and they reckon I’m the bees knees, ants pants and nits tits all rolled into one.
1955		Argus (Melbourne) 2 July 41/2: To make ‘ants’ pants’ or ‘cats pyjamas’ / To ‘beat the band’ choose Mallee farmers.
1960		A. Seymour One Day of the Year (1977) I i: Why does he look at me as if I’ma bad smell and he’s the bloody ant’s pants.
1982		N. Keesing Lily on the Dustbin 96: Just because she’s ‘as skinny as a walking hairpin’ or skinny as a ‘gas pipe cut on the bias’ or ‘a match-stick with all the wood shaved off’, you think she’s ‘the ants pants’.
1997		L. Davies Candy 119: I wore a suit and thought I looked like the ant’s pants.
2004		M. Lee Bedded by the Boss 120: They both thought he was the ant’s pants.
2010		S. Mayberry Her Best Friend 174: That’s how I feel. I think you're the bee’s knees. The cat’s pajamas. The ant’s pants.