Definition of "khat"

They are chewing on khat, a small serrated, bitter leaf with remarkable stimulative properties. […] One of the great things about khat […] is that after a good chew you need to do something—walking, running, chopping wood, vigorously reciting a poem, throwing a grenade, anything that requires boldness and physical initiative.

1967 July 9, Lawrence Fellows, “East Africa Turns On With Khat”, in The New York Times‎

Of course he was an amateur of quat – hashish – which delighted the cops.

1974, Lawrence Durrell, Monsieur, Faber & Faber, published 1992, page 31

‘And skinny Arab beggars who chew qat all day long to kill their appetites and get high on the weed.’

2004, Khushwant Singh, Burial at Sea, Penguin, published 2014, page 25

Habitually munching on narcotic leaves of khat, they are easy enough to spot, their gleaming Toyota four-wheel-drives slicing paths around beaten-up wheelbarrows and pushcarts.

2011 May 24, Jay Bahadur, “Somali pirate: 'We're not murderers… we just attack ships'”, in the Guardian‎