Staggered and troubled when overheard (6)
I believe the answer is:
phased
'staggered' is the definition.
Although both the answer and definition are past participle verbs, I don't see how they can define each other.
'troubled when overheard' is the wordplay.
I cannot really see how this works, but
'when' could be 'as' (eg 'when I walked' means 'as I walked') and 'as' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
'and' is the link.
Can you help me to learn more?
(Other definitions for phased that I've seen before include "spread over stages" , "Done in stages, shaped accordingly" , "Arranged in stages" , "Shaped (anag.)" , "Introduced in stages" .)