I like Greek a tiny bit (4)
I believe the answer is:
iota
'tiny bit' is the definition.
(an iota is a tiny piece)
'i like greek a' is the wordplay.
'like greek' becomes 'ot' (I can't justify this - if you can you should give a lot more credence to this answer).
'i'+'ot'+'a'='IOTA'
Can you help me to learn more?
(Other definitions for iota that I've seen before include "'Very small amount, jot (4)'" , "Foreign character" , "Just a jot, from Greek alphabet" , "Tiniest scrap" , "Ninth letter of Greek alphabet, small amount" .)