Teased foolishly for being placid (6)
I believe the answer is:
sedate
'being placid' is the definition.
(I've seen this before)
'teased foolishly' is the wordplay.
'foolishly' indicates an anagram.
'teased' is an anagram of 'SEDATE'.
'for' acts as a link.
(Other definitions for sedate that I've seen before include "Calm, sober" , "Dignified - staid" , "Give tranquilliser to" , "Tranquilise" , "Quiet and dignified" .)