冷淡 (lěng dàn): cold; indifferent

His attitude towards me suddenly became very cold; I don't know what happened.

The waiter at this restaurant had a cold attitude, which made us very uncomfortable.

She coldly declined his invitation without even giving a reason.

Although they used to be good friends, they have now become very distant.

His interest in this project seems very lukewarm; he is not very willing to participate.