Clear inventor (4)
I believe the answer is:
bell
This might be a double definition.
'clear' is the first definition.
The definition and answer can be both to do with contact as well as being verbs in their base form.
Perhaps you can see an association between them that I can't see?
'inventor' is the second definition.
(Alexander Graham Bell)
Can you help me to learn more?
(Other definitions for bell that I've seen before include "Stag's cry; ringer" , "bicycle accessory" , "He invented" , "Ringing device" , "Alternative to knocker" .)