Green’s Dictionary of Slang

to fail to understand, to find incomprehensible.

1729		Fielding Author’s Farce III i: in Works (1851) 844/1: Pray what is the design or plot? for I could make neither head nor tail on ’t .
1860		Hotten Dict. of Modern Sl. etc. (2nd edn).
1870		Hotten Sl. Dict.
1874		J. Greenwood Wilds of London (1881) 19: Her young man [...] had just expressed his inability ‘to make ’eds or tails on it’.
1888		Kipling ‘The Daughter of the Regiment’ in Plain Tales from the Hills 194: ‘We was a new an’ raw rigimint [...] an’ we cud make neither head nor tail av the sickness.’.
1895		C. Crowe Aus. Sl. Dict. 35: Head or Tail,‘I can’t make head or tail of it,’ can’t find it out.
1900		J. Conrad Lord Jim 86: Two officers came aboard, listened to the serang, tried to talk with the Arab, couldn’t make head or tail of it.
1957		G. Kersh Fowlers End (2001) 193: I know you were always a crank, you know, but sometimes I don’t know whether to make head or tail of you!
1959		W. Hall Long and the Short and the Tall Act I: I can’t make head nor tail of it.