In rebuilt patio regularly sunny for cactus (7)
I believe the answer is:
opuntia
'for cactus' is the definition.
(I've seen this before)
'in rebuilt patio regularly sunny' is the wordplay.
'in' is an insertion indicator.
'rebuilt' is an anagram indicator.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
The alternate letters of 'sunny' are 'un'.
'patio' is an anagram of 'optia'.
'optia' placed around 'un' is 'OPUNTIA'.
(Other definitions for opuntia that I've seen before include "prickly plant" , "Eg, prickly pear" , "Genus of cacti" , "Prickly-pear" , "Cactus of the prickly pear genus" .)