Adult right to feed metres from magic mushroom? (6)
I believe the answer is:
agaric
'mushroom?' is the definition.
(mushroom is a kind of agaric)
'adult right to feed metres from magic' is the wordplay.
'adult' becomes 'a' (abbreviation).
'right' becomes 'r' (abbreviation).
'to feed' means one lot of letters goes inside another (one word is fed by another set of letters).
'metres' becomes 'm'.
'from' is a deletion indicator.
'magic' with 'm' taken out is 'agic'.
'a'+'r'='ar'
'ar' inserted into 'agic' is 'AGARIC'.
(Other definitions for agaric that I've seen before include "Fungus of mushroom family" , "Fungus, eg, mushroom" , "fungal growth" , "Type of mushroom" .)