For setting the bird free outside, be teased (6)
I believe the answer is:
ribbed
'be teased' is the definition.
(I've seen this before)
'for setting the bird free outside' is the wordplay.
'for setting' becomes 'be' (I can't justify this - if you can you should give a lot more credence to this answer).
'free' indicates an anagram.
'outside' is an insertion indicator (some letters go outside others).
'bird' is an anagram of 'ribd'.
'be' placed inside 'ribd' is 'RIBBED'.
Can you help me to learn more?
(Other definitions for ribbed that I've seen before include "With ridges; teased" , "Like a sort of sweater" , "Ridiculed" , "such a jersey?" , "with rods" .)