I must stop careless lapse being spotted (6)
I believe the answer is:
espial
'i must stop' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'careless lapse being spotted' is the wordplay.
I cannot quite see how this works, but
'being' could be 'pia' (pia is a kind of being) and 'pia' is found within the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for espial that I've seen before include "secret observation" , "Seeing" , "look" , "notice" , "Spotting" .)