Blushing
'blushing' is the definition.
(blushing makes someone's face go red)
This is all the clue.
(Other definitions for red that I've seen before include "Crimson" , "Looking embarrassed" , "Flushed" , "- - poker: Kniphofia" , "could be a Marxist" .)
'blushing' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for red-faced that I've seen before include "Visibly embarrassed with ruddy complexion" , "Having glowing visage, embarrassed" , "Colourfully embarrassed" , "Visibly ashamed" , "Blushing" .)
'blushing' is the definition.
('redden' can be a synonym of 'blush')
This is the entire clue.