Merman, maybe? (5)
I believe the answer is:
ethel
'merman' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
(Other definitions for ethel that I've seen before include "Trying not to be seen" , "Lady" , "Dame --- Smyth; William Brown's sister" , "woman" , "Lethe (anag) -- Barrymore or Merman" .)