Rambling without company is natural (10)
I believe the answer is:
incoherent
'rambling' is the definition.
(similar in meaning)
'without company is natural' is the wordplay.
'without' means one lot of letters goes inside another.
'company' becomes 'co' (abbreviation).
'is natural' becomes 'inherent' (I've seen this before).
'co' going inside 'inherent' is 'INCOHERENT'.
(Other definitions for incoherent that I've seen before include "rambling" , "Internally inconsistent" , "drunk?" , "Confused" , "Unintelligible" .)