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

being analog (represented by a continuously variable physical quantity)

computer bug

slang; a slangy word

harness

A first-person pronoun used by a vassal who humbles himself to his master.

introduce

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

to worry, to fear

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