Quenya 

hloirë

venom, poison, poisonousness

hloirë noun "venom, poison, poisonousness" (PE17:185)

hloirë

noun. venom, poison, poisonousness

A noun in Quenya Notes (QN) from 1957 glossed “venom, poison(ousness)” derived from the root √SLOY (PE17/185). I think this applies to poison in the abstract, as opposed to hloima used for a specific venomous substance.

hloirëa

adjective. venomous, venomous, *poisonous

A word appearing in Quenya Notes (QN) from 1957 glossed “venomous”, an adjectival form of Q. hloirë “venom” (PE17/185).

Conceptual Development: The Qenya Lexicon of the 1910s had ᴱQ. henuva “venomous, poisonous”, an adjectival form of ᴱQ. heno (henu-) “venom, poison” (QL/38).

hloirëa

venomous

hloirëa adj. "venomous" (PE17:185)

Sindarin 

lhoer

noun. venom

n. venom, poison(ousness). Q. hloire.

Sindarin [(PE17 Sindarin Corpus) PE17:185] < SLOY. Group: Parma Eldalamberon 17 Sindarin Corpus. Published by

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!

Gnomish

fenog

adjective. venomous

A word appearing as G. fenog or {fembrin >>} fenwed “venomous” in the Gnomish Lexicon of the 1910s, an adjectival form of G. fem “venom (of snakes), poison in general” (GL/34).

Neo-Sindarin: For purposes of Neo-Sindarin, I would update this word to ᴺS. lhoereb “venomous, poisonous” based on the later word lhoer “venom, poison(ousness)”.

fenwed

adjective. venomous