Nosey creature is unable to stand missing start of conversation (7)
I believe the answer is:
antbear
'unable to stand missing start of conversation' is the definition.
I know nothing about this answer so I can't tell whether this works.
'nosey creature' is the wordplay.
'nosey' becomes 'ant' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'creature' becomes 'bear' (bear is a kind of creature).
'ant'+'bear'='ANTBEAR'
'is' acts as a link.
Can you help me to learn more?
(Another definition for antbear that I've seen is " Aardvark".)