An adjective for “yawning” appearing in the Markirya poem of the 1960s, probably an active participle of an otherwise unattested verb hac- or háca- “yawn” (MC/222).
Conceptual Development: In the version of the Markirya poem from around 1930, Tolkien used ᴱQ. yáme “yawning” (MC/214), replacing yape from the drafts of the poem (PE16/81).
A verb implied by the active participle hákala “yawning” from the Markirya poem of the 1960s (MC/222). The verb form is often assumed to be háca-, but if this adjective is in fact a present active participle (= “is currently yawning”), then the verb may be hac- instead.