A verb appearing only as akhaini “lay” in the first draft of the Lament of Akallabêth (SD/312). In later versions of the Lament it was change to the verb yad- “to go”, but since this replacement has a different sense, perhaps khay- remains valid.
This verb is only attested in the form akhaina “lay” and like all the draft verbs is difficult to analyze. Carl Hostetter and Patrick Wynne analyze its initial element as the 3rd-singular pronominal suffix a- and its final element -ni as a past tense marker (VSH/34, 37), also suggesting it may be derived from the Elvish root √KAY “lie (down)” (AAD/10). This Elvish derivation seems likely to me, but I think the form of the verb may instead be the draft-perfect.
Thorsten Renk suggested (NBA/35) the verb stem may instead be khain-. While he could be right about its use in the draft Adûnaic language, this doesn’t fit the later phonetic rules of Lowdham’s Report, which allow only long diphthongs in Classical Adûnaic (SD/423).