His funny hats are out of order! (6)
I believe the answer is:
thomas
'his' is the definition.
The definition suggests a singular noun which matches the answer.
'funny hats are out of order' is the wordplay.
'funny' is an anagram indicator.
'are out of' is an insertion indicator.
'order' becomes 'om' (Order of Merit).
'hats' anagrammed gives 'thas'.
'thas' enclosing 'om' is 'THOMAS'.
Can you help me to learn more?
(Other definitions for thomas that I've seen before include "Famous tank engine" , "Recipient of 10 21 [VELODROME GOLD]" , "Ancient writing instruments" , "The Apostle who initially doubted the Resurrection" , "West country novelist" .)