The antonyms for the phrase "look delighted" would denote a sad, disappointed, or even angry expression. Some of the antonyms that describe such emotions might include "frown," "scowl," "grimace," "glower," "sulk," "pout," "dishearten," "depress," "dismay," "irritate," and "disturb." These words convey a range of negative feelings that contrast with the joy or pleasure conveyed by the words "look delighted." They could be used to describe someone who has received bad news or has suffered a setback, or simply to represent a philosophical or pessimistic attitude towards life. The opposite of looking delighted is to convey a sense of gloom or dejection.