F1 Generation: The first generation children of two plants.

F2 Generation: Those plants resulting from the breeding of two F1 Generation plants.

Faced: UK slang meaning to be stunned by the potency of a hit or generally intoxicated after a long session.

Faded: To be high.

Fatty: Over packed joint.

Finger: A joint.

Flying Mexican Airlines: Getting stoned.

Fogout: To fill the room or car with smoke.

Four-Twenty (4:20) : The universal smoke-up time of day.

Fried: Extremely stoned.

FUBAR: UK slang: 'Fucked Up Beyond All Recognition'

Fuori di testa: Italian term for stoned.

Fumo: Italian Hash.