Colour that is not too upfront (4)
I believe the answer is:
tint
'colour' is the definition.
(tint is a kind of colour)
'that is not too upfront' is the wordplay.
'that is' becomes 'ti' (this could be a standard abbreviation of which I'm unaware).
'upfront' suggests taking the first letters.
The first letters of 'not too' is 'nt'.
'ti'+'nt'='TINT'
Can you help me to learn more?
(Other definitions for tint that I've seen before include "Quality of colour" , "Shade; colour slightly" , "(Softer variety of) colour" , "A slighth shade of colour" , "Hue, shade" .)