A noted heavyweight able to teach boys (4)
I believe the answer is:
eton
'able to teach boys' is the definition.
I can't tell whether this defines the answer.
'a noted heavyweight' is the wordplay.
'a noted' becomes 'e' (I can't justify this - if you can you should give a lot more credence to this answer).
'heavyweight' becomes 'ton' (I've seen this before).
'e'+'ton'='ETON'
Can you help me to learn more?
(Other definitions for eton that I've seen before include "learn here?" , "Posh English school of note" , "Leading English public school" , "School near Slough" , "Public school founded by Henry VI" .)