Green’s Dictionary of Slang

a glance, a look.

1895		Mirror of Life 14 Dec. 10/4: After a hand-shake Jem had a liker at Dan, and said [etc].
1905		Sporting Times 25 Mar. 2/3: I took a liker round the room, and was cheered to observe, gathered round one of the tables in the N.W. corner, a crowd of irresponsibles.
1912		E. Pugh City Of The World 237: And then there’s fellers like yourself [...] when they’ve had a liker at the latest, hand the paper back to me.