Red fruit carpet also's covered (6)
I believe the answer is:
tomato
'red fruit' is the definition.
(I've seen this before)
'carpet also's covered' is the wordplay.
'carpet' becomes 'mat' (I've seen this before).
'also' becomes 'too' (synonyms).
'covered' means one lot of letters goes inside another.
'mat' put into 'too' is 'TOMATO'.
(Other definitions for tomato that I've seen before include "A motto, strangely, for this fruit" , "Also called the love apple" , "Pulpy fruit eaten as vegetable" , "Love apple (archaic)" , "A motto turned out to be fruit or veg" .)