Green’s Dictionary of Slang

guiver n.2

[guiver adj.; note WWI milit. guyvo, a dandy]

a hairstyle, in which the hair is brushed forward over the forehead, affected by Cockney dandies; thus guiver-lad, a working-class dandy.

Show quotations
[UK]J. Ware Passing Eng. of the Victorian Era 3/2: The younger costers wear rival forehead tufts – such as the Quiff, the Guiver, or the Flop. There is, however, one golden rule for these fashions – the hair must stop short of the eyelids.

In phrases

put on the guiver (v.) (also put on the gyver)

(UK Und.) to show off, esp. to affect an upper-class accent.

Show quotations
[Aus]Sport (Adelaide) 10/4: They Say [...] That Pete P. and Daddy D. put on plenty of gyver when playing football.
[NZ]D. Davin Breathing Spaces 46: Wally called back in an extra-polite voice [...] he could put on the gyver so well when he wanted to.
[UK]D. Powis Signs of Crime 186: Guiver, put on the To pretend gentility or affect a ‘well-bred’ voice.