Early Quenya
qalúmea
adjective. deadly
qalmea
adjective. deathly
qalma
adjective. deadly
Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!
A set of related adjectives in the Qenya Lexicon of the 1910s: ᴱQ. qalma “deadly”, qalmea “deathly” and (archaic) †qalūmea equivalent to qalma, all based on ᴱQ. qalme or †qalume “death” (QL/76).
Neo-Quenya: Since [ᴹQ.] qualme “death” continued to appear in Tolkien’s later writings (Ety/KWAL), I’d adapt these adjectives as ᴺQ. qualmëa “deadly, deathly”, applied mainly to things apt to cause death.