Inoffensive points that can be a nuisance (6)
I believe the answer is:
mildew
'a nuisance' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'inoffensive points' is the wordplay.
'inoffensive' becomes 'mild' (I've seen this in another clue).
'points' becomes 'ew' (east and west, two compass points).
'mild'+'ew'='MILDEW'
'that can be' is the link.
Can you help me to learn more?
(Other definitions for mildew that I've seen before include "Fungal coating on plant" , "Fungus that produces mould on damp material" , "Fungal growth on plants" , "rot" , "threat to plants" .)