color up
verb1
To blush (to go red).
- Alice had already begun to colour up and was beginning to speak, when her Ladyship perceiving her displeasure, continued thus.1790, Jane Austen, “Jack and Alice”, in Juvenilia:
2
Card games, Poker To exchange a high number of low-value chips (of one color) for a lower number of higher value (of a different color), but keeping the same overall value.