tool / means / (cooking) secondary ingredient, such as spices, seasonings, and sauces / base

tool, ingredient

to inherit; to succeed (take over a position). See the variant form: 継ぐ.

foolish

foolishness, folly

(humble) I, me

introduce

to worry, to fear

Yu (a legendary ancient Chinese dynasty, founded by Shun) / A surname in Chinese

The katakana syllable グ (gu). Its equivalent in hiragana is ぐ (gu).