adjective noun burning, heat; fig. torment, torture, austerity.

1. (as nt.) Pv-a.98 (kāya ˚sankhāto tapo).
2. (as f.) tapanī Ja.v.201 (in metaphorical play of word with aggi & brahmacārin Com. visīvana-aggiṭṭha-sankhātā-tapanī).

to tapati & tapa