Landlord has no right to come in (5)
I believe the answer is:
enter
'come in' is the definition.
('enter' can be a synonym of 'come in')
'landlord has no right' is the wordplay.
'landlord' becomes 'ete' (I am not sure about this - if you are sure you should believe this answer much more).
'has' is an insertion indicator.
'no' becomes 'n' (common abbreviation).
'right' becomes 'r' (common abbreviation).
'ete' enclosing 'n' is 'ente'.
'ente'+'r'='ENTER'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for enter that I've seen before include "Take part in a contest" , "Register formally as a participant" , "Infiltrate" , "Fill in" , "submit?" .)