Loathe taking son for expedition (5)
I believe the answer is:
haste
'expedition' is the definition.
(expedition is expediting, doing something quickly)
'loathe taking son' is the wordplay.
'loathe' becomes 'hate' (I've seen this before).
'taking' is an insertion indicator.
'son' becomes 's' (genealogical abbreviation for son).
'hate' enclosing 's' is 'HASTE'.
'for' acts as a link.
(Other definitions for haste that I've seen before include "Rash speed" , "Hurriedness" , "Urgency of action" , "Urgent hurry" , "dispatch" .)