thin, weak, scarce, lacking (e.g., air, motivation, content)
都市部では人々の地域への帰属意識が希薄になりがちだ。
In urban areas, people's sense of belonging to the community tends to become weak.
to stagnate, to be stagnant, to be sluggish (water, air, atmosphere, speech)
彼のスピーチは時々言葉が澱んで、聞き取りにくかった。
His speech sometimes faltered (stagnated), making it difficult to understand.