Groans frightfully, finding skirtlike garment (6)
I believe the answer is:
sarong
'skirtlike garment' is the definition.
(I've seen this before)
'groans frightfully' is the wordplay.
'frightfully' is an anagram indicator.
'groans' is an anagram of 'SARONG'.
'finding' acts as a link.
(Other definitions for sarong that I've seen before include "Pacific islanders' garment" , "Malay cloth" , "Malay skirt-like garment" , "Unisex Malayan garment of cloth wrapped around body" , "Wrapped dress or skirt" .)