languor

A state of the body or mind caused by exhaustion or disease and characterized by a languid or weary feeling; lassitude; (countable) an instance of this.

languor of convalescence

Sometimes my pulse beat so quickly and hardly, that I felt the palpitation of every artery; at others, I nearly sank to the ground through languor and extreme weakness.

Melancholy caused by lovesickness, sadness, etc.; (countable) an instance of this.

Dullness, sluggishness; lack of vigour; stagnation.

I rushed towards her, and embraced her with ardour; but the deathly languor and coldness of the limbs told me, that what I now held in my arms had ceased to be the Elizabeth whom I had loved and cherished.

From languor she passed to the lightest vivacity; her temper became merry and wild in the extreme; she was all at once a tease, a tomboy, and a witch.

Listless indolence or inactivity, especially if enjoyable or relaxing; dreaminess; (countable) an instance of this.

It is earth's brief breathing space, after the heat and hurry of her busier time; like that repose known only to the young and happy, when the nerves gradually compose themselves, the thoughts gather into some vague but delicious train, and the eyes are closed by languor before sleep.

The languor of Youth—how unique and quintessential it is! How quickly, how irrecoverably lost! The zest, the generous affections, the illusions, the despair, all the traditional attributes of Youth—all save this—come and go with us through life; [...] but languor—the relaxation of yet unwearied sinews, the mind sequestered and self-regarding, the sun standing still in the heavens and the earth throbbing to our own pulse—that belongs to Youth alone and dies with it.

Heavy humidity and stillness of the air.

There is a languor in the air which encourages your own, and the poetry of memory is in every drooping flower and falling leaf.

[A] certain languor in the air hinted at an early summer.

To languish.