Nobody will observe when this is clear (5)
I believe the answer is:
coast
'clear' is the definition.
The definition and answer can be both to do with motion as well as being verbs in their base form.
Perhaps they are linked in a way I don't understand?
'nobody will observe when' is the wordplay.
I cannot really understand how this works, but
'when' could be 'as' (eg 'when I walked' means 'as I walked') and 'as' is found in the answer.
The remaining letters 'cot' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'this is' acts as a link.
(Other definitions for coast that I've seen before include "seaside area" , "Littoral region" , "Seashore; run downhill" , "(Of vehicle) move without using power" , "Move effortlessly" .)