Green’s Dictionary of Slang

1. used to intensify an adj., meaning very, completely, e.g. all fucked-up.

c.1850		F.M. Whitcher Widow Bedott Papers (1883) 231: So you mist that are all-killin’ genteel party last night?
1953		W. Eyster Far from the Customary Skies 299: I’m tard of you bein’ so all-blamed smart.
1997–2000		College Sl. Research Project (Cal. State Poly. Uni., Pomona) 🌐 All fawked up (adj.) Really drunk; really intoxicated; really high; totally obliterated. [Northern Michigan University, Marquette, MI].

2. nothing; usu. used in combs. to intensify an oath or obscenity; see bugger all n.; damn-all n.; fuck all n.

1939

J. Mulgan Man Alone 31: There’s all grows up here.

3. (orig. US campus) when retelling a story, used with the v. to be to denote something said or done, often describing an attitude or pose, sometimes used with an accompanying gesture, e.g. She was all shouting and I was all ‘No way!’.

1982		D.M. Alford Not Just Words Fall 1982-3 6: S/he's all, [with hands on hips and falsetto voice] ‘Why don't you ever do what you're told!’.
1992		Eble Campus Sl. Apr. 1: be all – a way of reporting speech. And he’s all, ‘shut up already’. And I’m all ‘get out of my face’.
1997–2001		Online Sl. Dict. 🌐 all v 1. to say. Notes: can only be used in the present, past, and future simple tenses and the past conditional tense. (Present simple: ‘He’s all, “I don’t know.”’ Past simple: ‘She was all, “I can’t go.”’ Future simple: ‘They’re going to be all, “You were right.”’ Past conditional: ‘We would have been all, “Why don’t you go?”’).