Prince blocking trouble for thirty days (5)
I believe the answer is:
april
'thirty days' is the definition.
(I've seen this before)
'prince blocking trouble' is the wordplay.
'prince' becomes 'pr'.
'blocking' means one lot of letters goes inside another (block can mean to plug a gap in something).
'trouble' becomes 'ail' (synonyms).
'pr' going into 'ail' is 'APRIL'.
'for' acts as a link.
(Other definitions for april that I've seen before include "period of time" , "Part of spring" , "Start of the second quarter" , "Thirty days in spring" , "time of the year" .)