Once more returning from Niagara (5)
I believe the answer is:
again
'once more' is the definition.
(synonyms)
'returning from niagara' is the wordplay.
'AGAIN' is hidden backwards in amongst the letters.
But, I am unsure how the hidden word is indicated.
Can you help me to learn more?
(Other definitions for again that I've seen before include "repeat order" , "Here we go ___" , "Predictably perhaps" , "second term" , "Not for the first time" .)