Definition
Also known as theme, this role describes the entity that undergoes action, or alternatively is moved, experienced, or perceived. (Carnie, 2006, p. 231)
All Sḵwx̱wú7mesh roots are inherently intransitive and consequently may only co-occur with one argument, which is realized as the subject. Thematically, this argument may be either an agent or a patient. (Jacobs, 2011, p. 48)
In Halkomelem, many roots such as k̓ʷáqʷ—‘get hit’ and kʷə́n—‘get taken’ are non-active or patient-oriented. (Suttles, 2004, p. 54)
Examples

References
Carnie, A. (2006). Syntax: A generative introduction. John Wiley & Sons.
Suttles, W. (2004). Musqueum reference grammar. UBC Press. SFU Student Access.