Green’s Dictionary of Slang

to act cautiously.

1785, 1788, 1796		Grose Classical Dict. of the Vulgar Tongue n.p.: Peer, to look about, to be circumspect.
1811		Lex. Balatronicum [as cit. 1785].
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue.