Top of column's black and yellow (6)
I believe the answer is:
craven
'yellow' is the definition.
(thesaurus)
'top of column's black' is the wordplay.
'top of' suggests taking the first letters.
'black' becomes 'raven' (I've seen this before).
The initial letter of 'columns' is 'c'.
'c'+'raven'='CRAVEN'
'and' is the link.
(Other definitions for craven that I've seen before include "Chicken-hearted" , "Lacking courage, cowardly" , "Mean-spirited" , "Contemptibly cowardly" , "Abjectly fearful" .)