Archenemy seems in trouble (7)
I believe the answer is:
nemesis
'arch-enemy' is the definition.
I can't tell whether this defines the answer.
'seems in trouble' is the wordplay.
'trouble' is an anagram indicator.
'seems'+'in'='seemsin'
'seemsin' with letters rearranged gives 'NEMESIS'.
Can you help me to learn more?
(Other definitions for nemesis that I've seen before include "Fate" , "Greek god of vengeance" , "Bane" , "rival who can't be beaten" , "Vengeful justice" .)