Socialist landlord’s special sort of day? (3-6)
I believe the answer is:
red-letter
'special sort of day?' is the definition.
I can't judge whether this defines the answer.
'socialist landlord's' is the wordplay.
'socialist' becomes 'red' (socialism is often associated with the colour red).
'landlord' becomes 'letter' (landlords let property).
'red'+'letter'='RED-LETTER'
Can you help me to learn more?
(Other definitions for red-letter that I've seen before include "(Sign of day that's) memorably important" , "This day is memorable due to scarlet missive" , "Scarlet missive to signal memorable day" , "This day is memorable - hence scarlet missive" .)