Concerned with seeing Carol upset about the middle of January (6)
I believe the answer is:
ocular
'concerned with' is the definition.
The answer and definition are not the same part of speech. However, past participle verbs and adjectives can occasionally mean the same thing.
'carol upset about the middle of january' is the wordplay.
'upset' indicates anagramming the letters.
'about' indicates putting letters inside.
'the middle of' indicates the central letters.
The middle letter of 'january' is 'u'.
'carol' with letters rearranged gives 'oclar'.
'oclar' going around 'u' is 'OCULAR'.
'seeing' acts as a link.
Can you help me to learn more?
(Other definitions for ocular that I've seen before include "Viewer" , "Glaucoma's such" , "Of the eye - visible" , "Relating to eyes or vision" , "not to be seen - due to this trouble?" .)