Brown gives thanks to the new leader (3)
I believe the answer is:
tan
'brown' is the definition.
(I know that tan is a type of light brown)
'thanks to the new leader' is the wordplay.
'thanks' becomes 'ta' (UK informal version of 'thank you').
'to' says to put letters next to each other.
'leader' suggests taking the first letters.
The first letter of 'new' is 'n'.
'ta'+'n'='TAN'
'gives' is the link.
(Other definitions for tan that I've seen before include "Prepare leather" , "function" , "Yellowish-brown colour" , "Light brown colour" , "Thrash" .)