Soak Pete's pants (5)
I believe the answer is:
steep
'soak' is the definition.
(steeping is a kind of soaking)
'pete's pants' is the wordplay.
'pants' indicates an anagram (UK informal term for 'nonsense' or 'rubbish').
'petes' with letters rearranged gives 'STEEP'.
(Other definitions for steep that I've seen before include "Soak thoroughly - precipitous" , "over the top" , "Vertiginous; excessive" , "not reasonable" , "Quickly rising" .)