Amateur Queen cover (5)
I believe the answer is:
layer
'cover' is the definition.
(thesaurus)
'amateur queen' is the wordplay.
'amateur' becomes 'lay' ('lay' can be similar in meaning to 'amateur').
'queen' becomes 'er' (abbreviation for Elizabeth Regina).
'lay'+'er'='LAYER'
(Other definitions for layer that I've seen before include "One producing eggs" , "Thickness of material or earth - relay it" , "See 22" , "Stratum; chicken" , "Film" .)