The lout seems empty-headed and a bit daft (3)
I believe the answer is:
oaf
'the lout' is the definition.
(synonyms)
'empty-headed and a bit daft' is the wordplay.
'empty-headed' becomes 'f' (I can't explain this - if you can you should give a lot more credence to this answer).
'and' is a charade indicator (letters next to each other).
'bit' becomes 'o' (resembles 0, a binary digit or bit).
'daft' indicates an anagram.
'a'+'o'='ao'
'ao' anagrammed gives 'oa'.
'f' put after 'oa' is 'OAF'.
'seems' is the link.
Can you help me to learn more?
(Other definitions for oaf that I've seen before include "Barbarian" , "A clumsy or stupid person" , "Clod" , "Boor or lout" , "Awkward stupid person" .)