1Cold, as of the weather or a place — used to describe low air temperature that one physically feels.
今日はとても寒いから、厚手のコートを着たほうがいい。
It's very cold today, so you should wear a heavy coat.
冬の朝の風が寒くて目が覚めた。
The winter morning wind was so cold it woke me up.
部屋が寒いので暖房をつけた。
The room was cold, so I turned on the heater.
北海道の冬はとても寒いと聞いた。
I heard that winters in Hokkaido are extremely cold.
2(colloquial) Uninteresting or lame — especially of a joke that falls flat and fails to get a laugh, leaving an awkward silence.
彼のギャグは寒くて誰も笑わなかった。
His joke was so lame that nobody laughed.
その一言で場の空気が寒くなった。
That one remark made the atmosphere go cold and awkward.
自分では面白いと思ったが、周りには寒いと言われた。
I thought it was funny myself, but everyone around me said it was lame.