He seems a bit silly to a bachelor (5)
I believe the answer is:
basil
'he' is the definition.
'seems a bit silly to a bachelor' is the wordplay.
'a bit' indicates taking the first letters (I've seen 'bit of' mean this).
'silly' becomes 'il' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'to a' means one lot of letters go next to another (I've seen this in other clues).
'bachelor' becomes 'ba' (the qualification: Bachelor of Arts).
The first letter of 'seems' is 's'.
's'+'il'='sil'
'sil' put after 'ba' is 'BASIL'.
Can you help me to learn more?
(Other definitions for basil that I've seen before include "Herb of mint family" , "named Cardinal Hume" , "Saint" , "A herb; Cardinal --- Hume" , "Aromatic leaves, used fresh or dried" .)