Full theatre allowed echo (7)
I believe the answer is:
replete
'full' is the definition.
(I know that full can be written as replete)
'theatre allowed echo' is the wordplay.
'theatre' becomes 'rep' (repertory theatre).
'allowed' becomes 'let' (to let is to allow or permit).
'echo' becomes 'e' (phonetic alphabet: alpha, bravo, charlie etc.).
'rep'+'let'+'e'='REPLETE'
(Other definitions for replete that I've seen before include "Fully satisfied" , "Sated by food" , "Full of food, gorged" , "Completely filled" , "Filled to satisfaction" .)