godan verb (-ru), intransitive verb
look sour; scowl; frown deeply
Describes a facial expression of strong displeasure, bitterness, or disgust. Often used when someone is clearly showing negative feelings on their face.
彼はまずい料理を一口食べて、苦り切った。
He took one bite of the bad food and scowled.
上司
All the employees looked sour at the boss's unreasonable demand.