Languor

A state of the body or mind which is caused by exhaustion of strength and characterized by a languid feeling; feebleness; lassitude; laxity.

Any enfeebling disease.

Listless indolence; dreaminess. Pope.

a feeling of lack of interest or energy

a relaxed comfortable feeling

oppressively still air; "the afternoon was hot, quiet, and heavy with languor"; "Summer shows all the languor of a hot, breezeless day as the dancer lazily brushes her hand over her brow"