i-adjective
Describes a person, expression, or atmosphere that is overly serious, rigid, or lacking warmth; often carries a slightly negative nuance of being pompous or humorless.
彼のしかつめらしい顔を見て、みんな笑いをこらえた。
Seeing his stern face, everyone stifled their laughter.
式典のしかつめらしい雰囲気に少し緊張した。
I felt a bit nervous in the solemn atmosphere of the ceremony.