Romeo emailed boss - it's meant to be therapeutic (8)
I believe the answer is:
remedial
'be therapeutic' is the definition.
(synonyms)
'romeo emailed boss it's meant' is the wordplay.
I cannot really see how this works, but
'romeo' could be 'r' (phonetic alphabet: alpha, bravo, charlie etc.) and 'r' is found in the answer.
an anagram of 'emailed' is 'emedial' which is within the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'to' acts as a link.
Can you help me to learn more?
(Other definitions for remedial that I've seen before include "Concerned with those with learning difficulties, for example" , "Medicinal" , "'Therapeutic, healing (8)'" , "regain lost ground" , "palliative" .)