Green’s Dictionary of Slang

1. extremely annoyed, furious.

1799		Sporting Mag. Nov. XV 87/1: A dun came – told him I would have some money soon – would not be gone [...] saw he was going to be savage, so kicked him down stairs to prevent his being impertinent.
1885		Bulletin (Sydney) 16 May 17/1: To imagine her dismay when she went into the cloakroom to get her traps before going home, upon discovering that one of the handsome strings had been ruthlessly torn from the hood! […] It wasn’t kind, was it, dear? and if it had been my hood I know I should have felt very savage about it.
1916		A. Brazil Luckiest Girl in School 141: ‘The match to-morrow will be all off!’ [...] ‘What a grizzly nuisance! Oh, the hard luck of it !’ ‘Kirsty’ll be as savage as we are!’.
1926		(con. 1860s) F.J. Wilstach Wild Bill Hickok 45: Well, he got savage mad about it and swore he would have his revenge.
1941		K. Tennant Battlers 99: The river-bank was in a savage mood.

2. strong, intense; thus savagely adv.

1994		(con. 1940s) K.C. Kearns Dublin Tenement Life 155: People were terribly poor. I saw savage hardship.
2000		F. Mac Anna Cartoon City 93: Don’t mind your woman here. She is savagely fucking pissed on Slippery Nipples. [Ibid.] 262: He passed the joint [...] ‘That’s savage shit,’ she coughed.
2016		C. Eble (ed.) UNC-CH Campus Sl. Spring 2016 8: SAVAGE — ruthlessly mean and adept in speech or action: ‘He was savage when he stood up to talk about what bothered him’ .

3. (Irish) impressive.

2017		L. McInerney Blood Miracles 40: ‘Did I tell you there’s new yokes coming in?’ he says. [...] ‘What’re they like?’ ‘Savage’.
2020		A. Killilea Boyo-wulf at https://boyowulf.home.blog 14 Feb. 🌐 ‘[W]ho the hell do ye think ye are now with all these fancy shields and metal shirts and feckin’ savage helmets on ye’.