In bed, a senior officer can be very persuasive (6)
I believe the answer is:
cogent
'very persuasive' is the definition.
'cogent' can be an answer for 'persuasive' (I've seen this before). I am not sure about the 'very' bit.
'in bed a senior officer' is the wordplay.
'in' is an insertion indicator.
'bed' becomes 'cot' (cot is a type of bed).
'a senior officer' becomes 'gen' (short for general, a senior army officer).
'cot' going around 'gen' is 'COGENT'.
'can be' is the link.
Can you help me to learn more?
(Other definitions for cogent that I've seen before include "Strong" , "Forceful - persuasive" , "Forceful and to the point" , "Powerful and convincing, argument say" , "Clearly argued" .)