to be irritated, to be annoyed or offended, to get angry, grumble; often in phrase ujjhāyati khīyati vipāceti expressing great annoyance Vin.i.53, Vin.i.62, Vin.i.73; Vin.ii.207; Vin.iv.226; SN.i.232 passim
■ SN.i.232 (mā ujjhāyittha); Ja.ii.15; Dhp-a.ii.20
aor ujjhāyi Ja.i.475; Dhp-a.ii.88;
inf ujjhātuṃ Ja.ii.355.
caus ujjhāpeti (q.v.).

ud + jhāyati¹ or perhaps more likely jhāyati² to burn, fig. to be consumed. According to Müller P. G pp. 12 & 42 = Sk. ava-; dhyā, but that is doubtful phonetically as well as semantically