LSJ
ἡ, easiness of temper, taking things easily, Th. 2.39.
recreation, relaxation, amusement, E. Cyc. 203, Ael. VH 9.9; in pl., αἱ ῥ. καὶ αἱ ἀπονίαι καὶ αἱ ἀμέλειαι Arist. Rh. 1370a14, cf. Isoc. 9.42, 45, Plb. 10.19.5. mostly in bad sense, indifference, sluggishness, laziness, Lys. 10.11, X. Mem. 3.5.5, al., cf. D. 9.5; ἐκτήσαντο ῥ. get a name for laziness, E. Med. 218.
heedlessness, rashness, τοῦ λόγου Pl. Phd. 99b. [Written ῥαθ- correctly in Phld. Rh. 2.31 S., Ir. p. 60 W., Hom. p. 28 O., IG 5(1).1208.33 (Gythium, i AD); Ion. ῥᾳθυμίη is dub. in Hp. Acut. 47 (cf. i p. lxxviii K.); this group of words is not found in Hdt. or other Ionic texts.]
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)