After slight depression, see dull person trying to be tactful (8)
I believe the answer is:
diplomat
'person trying to be tactful' is the definition.
I can't tell whether this definition defines the answer.
'after slight depression see dull' is the wordplay.
'after' means one lot of letters go next to another.
'slight depression' becomes 'dip' (I've seen this in another clue).
'see' becomes 'lo' (archaic exclamation meaning 'look!').
'dull' becomes 'mat' (mat as opposed to glossy).
'dip' next to 'lo' is 'diplo'.
'diplo'+'mat'='DIPLOMAT'
Can you help me to learn more?
(Other definitions for diplomat that I've seen before include "Tactful person, maybe in public service" , "State envoy" , "One deals tactfully with others" , "tactful one" , "Our Man in Havana" .)