legion \LEE-jehn\ (adjective) - Multitudinous, of enormous number.
"My doubts about this project are legion; I don't know where to begin."
From Latin legio, legionis "a body of soldiers numbering 10 cohorts and 300 cavalry." A cohort comprised 300-600 men. From Latin lego "I gather, collect" based on Proto-Indo-European *leg- which seems to underlie "lecture," "legend," "loyal," "logic," and maybe "leech." The root is also somehow related to speech, as in Greek "lexicon" and "logos" (word, idea) and, via a collection of laws, "legal" and "legislate" from Latin lex, legis "law." The noun, "legion," is used frequently but the adjective has all but fallen by the wayside. The noun is maintained by phrases like "American Legion" and "Legion of Honor" but no similar phrases to support the adjectival use. It is also little used because its distribution in sentences is limited to predicate position; it is never placed before a noun (use the noun here: "a legion of questions") but only after a copula, "My questions are legion."