Abundant firm and very good (7)
I believe the answer is:
copious
'abundant' is the definition.
(similar in meaning)
'firm and very good' is the wordplay.
'firm' becomes 'co' (a firm is a company).
'and' says to put letters next to each other.
'very good' becomes 'pious' (pious can mean very religious).
'co'+'pious'='COPIOUS'
(Other definitions for copious that I've seen before include "good measure" , "Plentiful, existing in large amounts" , "Many" , "Abundant in quantity" , "Abundant in supply" .)