Ring operator, ringing round, hinting at trouble (7)
I believe the answer is:
ominous
'hinting at trouble' is the definition.
I can't tell whether this definition defines the answer.
'ring operator ringing round' is the wordplay.
I cannot quite see how this works, but
'ring' could be 'o' and 'o' is present in the answer.
'round' could be 'o' (round can mean a round object) and 'o' is present in the answer.
The remaining letters 'minus' 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).
Can you help me to learn more?
(Other definitions for ominous that I've seen before include "Threatening disaster" , "Portending bad things" , "Boding badly, menacing" , "Portending evil" , "Threatening or foreshadowing evil or tragedy" .)