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!

Qenya 

hríma

adjective. many, very numerous (great in number or quantity)

An adjectival form of ᴹQ. hrim- appearing in Demonstrative, Relative, and Correlative Stems (DRC) from 1948 (PE23/106).

Neo-Quenya: For purposes of Neo-Quenya I would use ᴹQ. rimba “numerous” from The Etymologies, since this is more compatible with Tolkien’s usual form of the root: ᴹ√RIM.