Expedition has only half a tent (5)
I believe the answer is:
haste
'expedition' is the definition.
(expedition is expediting, doing something quickly)
'has only half a tent' is the wordplay.
'only half' suggests halving the letters.
'tent' with half the letters taken is 'te'.
'has'+'te'='HASTE'
(Other definitions for haste that I've seen before include "Promptitude" , "Leader abandons modest" , "Heats (anag.)" , "Over-eager speed" , "Rash speed" .)