Esperanto: ARNIK is not a real Esperanto word

[HaleyHalcyon]

Esperanto words, save for a few interjections, end with specific word endings:

• -o for nouns, -oj for plural nouns, -on for nouns in the accusative case, -ojn for plural and accusative
• -a for adjectives, same logic for -aj, -an, -ajn
• -e for adverbs, -en for adverbs indicating “motion into”
• -i for infinitive verbs, -is for past tense verbs, -as for present tense verbs, -os for future tense verbs, -us for conditional tense verbs
• -u for imperative verbs

Today’s Esperanto answer was ARNIK, which has none of these word endings, and is not one of the special words. The ReVo has this definition for “arniko”: “leopard's bane, arnica”, but ARNIK alone is not a valid word. The Esperanto dictionary needs to be completely replaced.