Quenya 

heca

interjection. be gone!, stand aside!

An imperative exclamation meaning “be gone!, stand aside!” derived from the root √HEK “aside, apart, separate” (WJ/361, 364). Since the root was not verbal, this is probably a fossilized form, based on an ancient suffixed imperative ✶hek(e) ā. The modern Quenya verb form derived from the root √HEK is hehta- “put aside, leave out, exclude, abandon, forsake” (WJ/365).

Tolkien said heca “often appears in the forms hekat sg. and hekal pl. with reduced pronominal affixes of the 2nd person” (WJ/364). This is the only place he used a pronominal suffix with a suffixed imperative, making this construction somewhat dubious, especially since it seems hec- itself is not a verb. I would assume these are additional fossilized forms. As further evidence of their fossilized nature, the sg. suffix -t(ye) seems to be used imperiously as it was in ancient language, as opposed to affectionately as it was in modern Quenya. Furthermore, the reduced suffix -l is plural rather than singular-polite as it was in modern Quenya.

Conceptual Development: There was a similar-meaning interjection ᴱQ. {avavanda >>} avande “get hence!” in the Qenya Lexicon of the 1910s under the early root ᴱ√AVA “go away, depart, leave” (QL/33).

heca!

be gone! stand aside!

heca! ("k") vb. in imperative "be gone! stand aside!", also with pronominal suffixes hecat sg. (but see -t #3) and hecal pl. (WJ:364)