Passions-
1.Excessive intrinsic heat (in the soul-units) due to Rāga (attachment) and Dveṣa (aversion); (it is fourfoldanger, conceit, deceit and greed), by which, there is an influx of kaṣa, i.e.. Karma.
rāgadveṣātmakottāpaḥ kaṣāyaḥ.
(Jaisidī 4.23)
kaṣaḥ karma bhavet tasya āyo- lābhaḥ prāptiḥ kaṣāyaḥ.
(Tabhā 6.5 Vṛ)
2.The impulse of Moha (delusion) which stains (vitiates) the consciousness (soul) with its own colour (the vitiating effect).
kalnṣayanti śuddhasvabhāvaṃ santaṃ karmamalinaṃ kurvanti jīvamiti kaṣāyaḥ.
(Prajñā 14.1 Vṛ Pa 290)