Adjective

-gumu (declinable)

1) hard

Inflection

Inflected forms of -gumu

Noun class | singular | plural

M-wa class | mgumu | wagumu

M-mi class | mgumu | migumu

Ma class | gumu | magumu

Ki-vi class | kigumu | vigumu

N class | ngumu | ngumu

U class | mgumu | ngumu

Pa class | pagumu | pagumu

Ku class | kugumu | kugumu

Mu class | mugumu | mugumu

From Wiktionary: https://en.wiktionary.org/wiki/gumu

Kiswahili ni kigumu

I wrote "English is tough," which can mean difficult, but it didn't take it.