Vibhaṅgasutta

Suttapiṭaka · Saṁyuttanikāya · Mahāvaggasaṁyutta · Vol. 19 · Section 1193

[1193] And what, bhikkhus, is the overly slack (atilīna) mind (citta)? Whatever mind, bhikkhus, is accompanied by laziness (kosajja) and associated with laziness — this, bhikkhus, is called the overly slack mind.

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.

This passage also appears in 1 other place

Vol. 19 · Section 1180 — Vibhaṅgasutta