Putrid, rotten salami concealing millions (7)
I believe the answer is:
miasmal
'putrid' is the definition.
(thesaurus)
'rotten salami concealing millions' is the wordplay.
'rotten' is an anagram indicator.
'concealing' is an insertion indicator.
'millions' becomes 'm' (abbreviation).
'salami' is an anagram of 'miasal'.
'miasal' going around 'm' is 'MIASMAL'.
(Other definitions for miasmal that I've seen before include "with unhealthy air" , "like stink" , "In such bad air" .)