Green’s Dictionary of Slang

1. relevant to membership of the sporting fraternity.

1832

Egan Bk of Sports 188: It was soon whispered about that [...] it was dangerous to be safe.

2. denoting approval, the overall implication is of being socially acceptable to a given peer group.

1846		Swell’s Night Guide 60: cracksman: If she was to tumble to you widding about her, she’d mug you like a shot. Wouldn’t she Sall? shake: Safe, and no nunks. She can slog and no flies.
1863		Story of a Lancashire Thief 8: Of course the crib was safe, and one of the slaveys ogling to give the office if any bobbies should pass.
1873		Sl. Dict. 275: Safe trusty, worthy of confidence. [...] A safe man among betters is one who is sure to fulfil his engagements.
1911		G. Bronson-Howard Enemy to Society 173: No senator was deemed fit to represent the Empire State at the nation’s capital unless Room 203 approved him as a ‘safe’ man.
1917		F. Packard Adventures of Jimmie Dale (1918) I vii: They dealt with him, the crooks, while they swore to ‘get’ him because he was ‘safe’.
1926		J. Black You Can’t Win (2000) 127: Why not spend a hundred dollars for fare to pocatello and back? [...] Mary’s safe.
1952		C. Hamilton Men of the Und. 324: Safe, Reliable.
1976		P. Theroux Family Arsenal 254: ‘They’re safe,’ said Hood. ‘They know what they’re doing.’.
1983		J. Matthews The Park and Other Stories (2nd edn) 40: Dose whities safe.
1992		in R. Graef Living Dangerously 89: I’m a pretty safe person.
1994		P. Baker Blood Posse 281: Take it easy [...] The brother is safe.
2017		hubpages.com ‘Roadman Slang 4 Jun. 🌐 Safe - when someone is nice and trustable. ‘Those guys are so safe, let's invite them with us tonight’.
2020		G. Krauze What They Was 191: Your pops is mad safe.

3. satisfactory, pleasant.

1958		A. Sillitoe Sat. Night and Sun. Morning 127: The Horse and Groom would be a safe bet for noise on Sunday night.
1992		in R. Graef Living Dangerously 172: In three months things could be safe.
1997		C. Newland Scholar 195: ‘How’s it feel to be home?’ [...] ‘It’s safe star.’.
2007		Skins ser.1 ep.1 [TV script] Can I get you some rum punch? I'm afraid we're getting rather giggly on it - isn't that safe!
2015		www.reddit.com/r/hiphopheads Grime Terminology Guide 🌐 Safe - When describing something/someone that is cool, or agreeing with something. Also as a greeting (E.g. safe man, how you doing?).

4. (US Und.) untraceable, e.g. of an unlicensed gun.

1969

M. Puzo Godfather 109: Tonight, just in case he could finish off the job, he wanted a ‘safe’ gun. One that could not possibly be traced.

5. used in sex contact advertisements to mean the man advertising has had a vasectomy.

1999

neris ‘The Advertising Alphabet’ 15 Oct. on ‘GenQuest’ at Yahoo! Groups 🌐 Safe Has had vasectomy.