Guard posted in hotel not powerful (8)
I believe the answer is:
sentinel
'guard' is the definition.
(sentinel is a kind of guard)
'posted in hotel not powerful' is the wordplay.
I cannot quite understand how this works, but
'posted' could be 'sent' ('send' can be a synonym of 'post') and 'sent' is located in the answer.
'in' is found in the answer.
The remaining letters 'el' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for sentinel that I've seen before include "Watching guard" , "Watchperson" , "Soldier who stands and keeps watch" , "Look-out, military guard" , "Sentry" .)