Mystification shown by a pair of fellows among British lot missing a leader (10)
I believe the answer is:
bafflement
'mystification' is the definition.
(synonyms)
'a pair of fellows among british lot missing a leader' is the wordplay.
I cannot quite see how this works, but
'a' is within the answer.
'fellows' could be 'men' (fellow can mean a man) and 'men' is present in the answer.
'british' could be 'b' (abbreviation e.g. in 'BBC') and 'b' is present in the answer.
'leader' could be 'f' (I have seen 'German leader ' mean 'f' so perhaps 'leader' could also mean 'f') and 'f' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
'shown by' is the link.
Can you help me to learn more?
(Other definitions for bafflement that I've seen before include "Total bewilderment" , "Utter perplexity" .)