Latest: nephew that is detained by nuns for causing trouble (12)
I believe the answer is:
inconvenient
'causing trouble' is the definition.
(I've seen this before)
'latest nephew that is detained by nuns' is the wordplay.
I cannot really see how this works, but
'that is' could be 'ie' (short for Latin 'id est', 'that is') and 'ie' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
'for' acts as a link.
(Other definitions for inconvenient that I've seen before include "Inopportune" , "Causing trouble" , "Awkward" , "Causing difficulties" , "Causing slight difficulty" .)