Lowness and decline with 低
低 conveys the meanings of low or to decrease in terms of position, degree, or value.
Etymology
This kanji is a phono-semantic compound comprised of 亻 (person) and 氐 (bottom)
Decrease
低下 (Decline)
低下 means a decline or drop in value, level, quality, or degree.
It combines 低 (low) with 下 (down) to show something going downward.

Jumbo helps his friend Yousuke move into his new house. After unboxing things, Yousuke stops for a break.
- 葉介
( : - 「なんか俺
( 体力( 低下( してんなあ… 手( がふるふる…」- “Man, I feel like my stamina is dropping... My hands are shaking...”
- ジャンボ:
- 「おまえさ 近所
( にあいさつで配( る粗品( とか用意( してるか?」- “Hey, are you preparing any little gifts to hand out to your neighbors when you go around saying hello?”