Green’s Dictionary of Slang

1. bizarre, eccentric, strange.

1925		L. Mackay Mourne Folk 109: Now there was a lump of a hussy [...] a far-out friend of Peter’s wife, lived in the house with them.
1956		H. Gold Man Who Was Not With It (1965) 273: Grack told me you’re far out, boy.
1959		A. Zugsmith Beat Generation 24: Maybe we’ll meet again some day – and you’ll read your gone poetry or far-out philosophy.
1961		T. Taylor Baron’s Court All Change (2011) 69: [A] writer who could never get anything published because it was too far out.
1967		M. Braly On the Yard (2002) 5: As if they sensed some violent far-out freakishness thrashing around in his hectic yellow eyes.
1976		N. Thornburg Cutter and Bone (2001) 123: The whole idea [...] It’s pretty far out.
1987		A. Rollini Big Bands 70: These girls came out and invited me in. One of them was calling to an imaginary dog. These girls were far out.
1991		B. Stewart Broken Arse I ii: Hey bro, that’s a far out name of mine—very far out.
1997–2001		Online Sl. Dict. 🌐 far out adj [...] 2. strange. (‘That movie is really far out.’).
2002		D.H. Sterry Chicken (2003) 102: Wow, that sounds ... far out.

2. extreme.

1965		L. Bruce How to Talk Dirty 61: Seven of the farthest-out Tillie and Mac books I’d ever seen.
1977		(con. 1969) M. Herr Dispatches 64: Between the farout things you saw or heard and what you personally lost out of all that got blown away, the war made a place for you that was all yours.

3. (US drugs) of an habituated narcotcis user, completely overwhelmed by addiction.

1978

R.D. Pharr Giveadamn Brown (1997) 38: Her one leg was ulcerated, the giveaway sign of the farthest-out junkie.