Gnomish
heleg
noun. ice
geluim
masculine name. Ice
helc
noun. ice
helon
adjective. frozen
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!
An adjective in the Gnomish Lexicon of the 1910s appearing as G. helon “frozen”, an adjectival form and possibly a passive participle of G. hel- “freeze” (GL/48).
Neo-Sindarin: For purposes of Neo-Sindarin, I think it is best to update this to the Sindarin passive-participle form ᴺS. hellen “frozen”.