懈怠

Adjective

 * 1) slack; sluggish; remiss; lax

Etymology 1
From compound. The kan'on, so likely a later borrowing.

Noun

 * 1)  laches: a kind of lapse wherein an opposing party has neglected to invoke its rights within a certain period of time
 * 2)  negligence
 * 3) laziness, idleness, carelessness

Usage notes
The Japanese Wikipedia article 懈怠 (法学) describing the legal and  senses uses the ketai reading. However, dictionaries tend to list kaitai as the primary reading for the legal senses.

Etymology 2
From compound. A mixed reading, so likely a later development within Japanese. Uses the goon of ke for the first half, and the kan'on of tai for the second half.

Noun

 * 1) laziness, idleness, carelessness
 * 2)  laches: a kind of lapse wherein an opposing party has neglected to invoke its rights within a certain period of time
 * 3)  negligence
 * 4)  spiritual slothfulness: kausidya

Usage notes
The kedai reading below is more common for the Buddhist spiritual slothfulness sense.

Verb

 * 1) to be lazy, to be careless

Etymology 3
From compound. The goon, so likely the original borrowing.

Noun

 * 1)  spiritual slothfulness: kausidya
 * 2) laziness, idleness, carelessness

Usage notes
The ketai reading above is more common for the sense.