Second XI shows power (5)
I believe the answer is:
steam
'power' is the definition.
(I've seen this before)
'second xi' is the wordplay.
I cannot quite see how this works, but
'second' could be 's' (common abbreviation) and 's' is found within the answer.
The remaining letters 'team' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
'shows' is the link.
Can you help me to learn more?
(Other definitions for steam that I've seen before include "What powered old engines" , "Water vapour; impetus" , "Form of water" , "Type of power" , "Speed" .)