Pensioner's more scary when upset about tobacconist's closing (7)
I believe the answer is:
retiree
'pensioner's' is the definition.
(I've seen this in another clue)
'more scary when upset about tobacconist's closing' is the wordplay.
'more scary' becomes 'eerier' (I've seen this in another clue).
'when upset' says the letters should be written backwards (in a down clue - set, written, up).
'about' means one lot of letters goes inside another.
'closing' suggests the final letters (the letter which ends or closes the word).
The last letter of 'tobacconist' is 't'.
'eerier' reversed gives 'reiree'.
'reiree' placed around 't' is 'RETIREE'.
(Other definitions for retiree that I've seen before include "Person out of work" , "One ceasing to work" , "One having completed work" , "Pensioner" , "One put out to pasture" .)