Strip found in undergrowth on Guam (5)
I believe the answer is:
thong
'strip' is the definition.
(I've seen this in another clue)
'in undergrowth on guam' is the wordplay.
'in' says the answer is hidden in the clue.
'THONG' is hidden within 'undergrowth on guam'.
'found' acts as a link.
(Other definitions for thong that I've seen before include "Insubstantial underwear" , "Skimpy underwear" , "Narrow strip of leather (or other material)" , "Skimpy undergarment" , "Beachwear item" .)