Unsuitable party men not in the House? (7)
I believe the answer is:
outdoor
'not in the house?' is the definition.
'unsuitable party men' is the wordplay.
'unsuitable party' becomes 'outdo' (I am not sure about this - if you are sure you should believe this answer much more).
'men' becomes 'OR' (military abbreviation for Other Ranks).
'outdo'+'or'='OUTDOOR'
Can you help me to learn more?
(Other definitions for outdoor that I've seen before include "Not done in the house" , "in the garden, say" , "Done in the open" , "not under cover" , "External" .)