General Embarrassment:
* Ashamed
* Flustered
* Awkward
* Self-conscious
* Mortified
* Humiliated
* Abashed
* Sheepish
* Blushing
More Intense Embarrassment:
* Red-faced
* Cringeworthy
* Dejected
* Chagrined
* Discomfited
* Shamefaced
More Specific:
* Flustered: Feeling nervous and confused, often due to a sudden event.
* Awkward: Feeling uncomfortable or embarrassed due to clumsiness or a social faux pas.
* Mortified: Feeling deeply ashamed or humiliated.
* Humiliated: Feeling degraded or belittled.
* Sheepish: Feeling shy or embarrassed, often after doing something wrong.
* Blushing: Showing embarrassment by turning red in the face.
The best synonym will depend on the specific situation and the level of embarrassment you want to express.