It's for putting on, e.g. at Lincoln (5)
I believe the answer is:
green
'it's for' is the definition.
I can't judge whether this defines the answer.
'on e g at lincoln' is the wordplay.
'on' means one lot of letters goes inside another (as in clothing 'on' a person).
'at lincoln' becomes 'ren' (I can't justify this - if you can you should give a lot more credence to this answer).
'g'+'ren'='gren'
'e' going into 'gren' is 'GREEN'.
'putting' is the link.
Can you help me to learn more?
(Other definitions for green that I've seen before include "Party label" , "Ecologically sound" , "Eg, avocado, emerald" , "Between blue and yellow in the colour spectrum" , "raw, as > part of course" .)