Sailor with a solitary decorative shell (7)
I believe the answer is:
abalone
'decorative shell' is the definition.
'abalone' can be an answer for 'shell' (I've seen this before). I'm not sure about the 'decorative' bit.
'sailor with a solitary' is the wordplay.
'sailor' becomes 'ab' (abbreviation for able seaman).
'with' says to put letters next to each other.
'a solitary' becomes 'alone' (I've seen this before).
'ab'+'alone'='ABALONE'
Can you help me to learn more?
(Other definitions for abalone that I've seen before include "Edible mollusc - on a bale (anag)" , "Ormer, ear shell" , "something to eat from the sea" , "Would you be able on a US shellfish?" , "Edible marine mollusc -- Oban ale (anag)" .)