He has a habit of taking things (6)
I believe the answer is:
addict
'he has a habit of taking things' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he has a habit of taking things' is the wordplay.
'he' becomes 'Ad'.
'has' says to put letters next to each other.
'a habit of taking things' becomes 'dict' (I can't justify this - if you can you should give a lot more credence to this answer).
'ad'+'dict'='ADDICT'
Can you help me to learn more?
(Other definitions for addict that I've seen before include "One who is dependent on something, alcohol say" , "Person with compulsive dependence on drugs" , "Drug dependant" , "Bricklayer's tool" , "Junkie, dependant" .)