甚だしい
はなはだしい · hanahadashii · JLPT N2 · i-adj
extreme
はなはだ (very much) + しい (adjective ending) = extreme, excessive, terrible
はなはだ is an adverb meaning very much. Adding the adjective ending しい turns it into a word for something that goes past normal limits. Read it as hana-hada plus shii: very-much-ish.