Woman at tax office gives orange dye (7)
I believe the answer is:
annatto
'orange dye' is the definition.
The definition suggests a singular noun which matches the answer.
'woman at tax office' is the wordplay.
'woman' becomes 'ann' (woman's name).
'tax office' becomes 'to' (this could be a standard abbreviation of which I'm unaware).
'ann'+'at'+'to'='ANNATTO'
'gives' is the link.
Can you help me to learn more?
(Other definitions for annatto that I've seen before include "dyestuff" , "tree" , "Orange colouring" , "Colouring matter" , "Food dye from red pulp of tropical fruit" .)