All wrong about some boy being faithful (5)
I believe the answer is:
loyal
'being faithful' is the definition.
(similar in meaning)
'all wrong about some' is the wordplay.
'wrong' indicates an anagram.
'about' means one lot of letters goes inside another.
'some' becomes 'oy' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'all' anagrammed gives 'lal'.
'lal' placed around 'oy' is 'LOYAL'.
'boy' is the link.
Can you help me to learn more?
(Other definitions for loyal that I've seen before include "Dedicated" , "Unwaveringly devoted to friend or cause" , "True to one's country etc" , "Staunch" , "Alloy (anag.)" .)