Stick plug in this place (6)
I believe the answer is:
adhere
'stick' is the definition.
(to adhere to something is to stick to it)
'plug in this place' is the wordplay.
'plug' becomes 'ad' (as in plugging a product).
'in this place' becomes 'here' (synonyms).
'ad'+'here'='ADHERE'
(Other definitions for adhere that I've seen before include "Bond" , "Stick fast (to something)" , "Stick to, remain loyal" , "Stick with header" , "'Stick to, a play say (6)'" .)