Vague sense to gather up American lubricant (8)
I believe the answer is:
nebulous
'vague' is the definition.
(synonyms)
'sense to gather up american lubricant' is the wordplay.
I cannot quite understand how this works, but
'american' could be 'us' (abbreviation for United States) and 'us' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for nebulous that I've seen before include "Cloudy; hazy" , "Cloudlike; vague" , "Vague, lacking a distinct shape" , "Cloudy and vague" , "Hazy, like a cloud" .)