Formed of units mostly produced from a mould ~n right? (7)
I believe the answer is:
modular
'formed of units mostly produced from a' is the definition.
I can't judge whether this defines the answer.
'mould n right?' is the wordplay.
I cannot really see how this works, but
an anagram of 'mould' is 'modul' which is located in the answer.
'right?' could be 'ar' (I've seen this in other clues) and 'ar' is found in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for modular that I've seen before include "Made of units" , "Built from separate units" , "Made from detachable pieces" , "in several parts" .)