Odd men out, sirs sadly taken amiss (13)
I believe the answer is:
misunderstood
'taken amiss' is the definition.
('misunderstand' can be a synonym of 'take amiss')
'odd men out sirs sadly' is the wordplay.
'sadly' indicates anagramming the letters.
'odd'+'men'+'out'+'sirs'='oddmenoutsirs'
'oddmenoutsirs' with letters rearranged gives 'MISUNDERSTOOD'.
(Other definitions for misunderstood that I've seen before include "Not correctly comprehended" , "Failed to comprehend" , "Failed to construe meaning correctly" , "Read wrong" , "Failed to see the right meaning" .)