Green’s Dictionary of Slang

wellie n.

also welly, welly-boot, wellygog

a wellington boot.

[UK]I. & P. Opie Lore and Lang. of Schoolchildren (1977) 175: Wellygogs (Wellington boots).
[UK]T. Keyes All Night Stand 19: Shut up or I’ll smack you round the gob with a welly.
[UK]Beano 3 Apr. 13: Here’s a pair of wellies to keep your feet dry.
[UK]C. McPherson The Weir 49 : He gave us leggings and wellies and the whole bit.
[UK]Indep. Rev. 19 Jan. 11: Clad in dinky white wellies, sou’westers, and naughty see-through plastic macs.
[UK]J. Fagan Panopticon (2013) 140: They’ve both got cute wee welly-boots on.
[UK]J. Fagan Panopticon (2013) 211: I could fucking leather that posh cunt. She’s got stupid designer wellies on.
[UK]V. McDermid Insidious Intent (2018) 213: Have u got wellies?

In phrases

give it some welly (v.) [abbr.; phr. underlined by an extra image of the ‘wellie-chucking’ contests that have become popular]

to apply more force, energy or effort.

[UK]Guardian 7 Oct. [Internet] Thomas Gravesen gives it some welly, but it’s always rising and fizzes over the bar.
[Ire]P. Howard Curious Incident of the Dog in the Nightdress 299: I stort giving it serious amounts of welly in the old chatting-up deportment.
give someone the welly (v.)

to reject, to get rid of; to dismiss.

[UK]A. Close Official and Doubtful 55: He was heid bummer at the Welfare Rights but they gave him the welly: sexual harassment of a lassie on the YTS.