Hypothetical mood (abbreviated HYP) is an epistemic grammatical mood found in some languages (for example Lakota) which indicates that while a statement is not actually true, it could easily have been.^[1] For instance, in English, "You know you shouldn't play with knives! You could have hurt someone!" conveys a meaning that would be expressed with the hypothetical mood in Lakota.

References

^ Loos, Eugene E.; Anderson, Susan; Day, Dwight H. Jr.; Jordan, Paul C.; Wingate, J. Douglas. "What is hypothetical mood?". Glossary of linguistic terms. SIL International. Retrieved 2009-12-28.

Linguistic modalities and grammatical moods

Realis
(what is)

Irrealis

Deontic (what should be)	Benedictive Commissive (promises, threats) Directive (commands, requests, requirements) Debitive Deliberative Dynamic Hortative (+ subtypes) Imperative Injunctive Jussive Necessitative Permissive Precative Prohibitive Propositive Volitive (hopes, wishes, fears) Desiderative Imprecative Optative
Epistemic (what may be)	(inferences, possibilities, questions, etc.) Alethic Assumptive Deductive Dubitative Hypothetical Inferential/renarrative/oblique Interrogative Potential Speculative Subjunctive
Dependent circumstances (what would be)	Conditional Eventive