Joins without one's dramatic precepts (7)
I believe the answer is:
unities
'dramatic precepts' is the definition.
Although both the answer and definition are plural nouns, I don't see how they can define each other.
'joins without one's' is the wordplay.
'joins' becomes 'ie' (I am not sure about this - if you are sure you should believe this answer much more).
'without' indicates putting letters inside (some letters go outside or 'without' others).
'one's' becomes 'unit's' ('unit' can be a synonym of 'one').
'ie' placed into 'units' is 'UNITIES'.
Can you help me to learn more?
(Another definition for unities that I've seen is " limitations of certain theatre".)