Systems of grime spread on directions (7)
I believe the answer is:
regimes
'systems' is the definition.
The definition and answer can be both related to thinking as well as being plural nouns.
Maybe you can see an association between them that I don't see?
'grime spread on directions' is the wordplay.
'spread' indicates an anagram.
'on' means one lot of letters go next to another.
'directions' becomes 'es' (east and south - two directions).
'grime' anagrammed gives 'regim'.
'regim'+'es'='REGIMES'
'of' is the link.
Can you help me to learn more?
(Other definitions for regimes that I've seen before include "Systems of government or courses of treatment" , "Governments in power" , "rules" .)