godan verb (-ru), intransitive verb
Describes something becoming curved or warped, often due to heat, moisture, or pressure. Used for objects like boards, paper, or metal.
湿気で床板が反ってしまった。
The floorboards warped from the humidity.
The book cover is warped from sun exposure.
godan verb (-ru), intransitive verb
bend backward; arch one's back
Used for a person or body part bending backward, such as arching the back or bending fingers backward. Often implies an extreme or flexible bend.
彼は背筋を伸ばして、体を後ろに反らせた。
He straightened his back and bent his body backward.
指が反るほど柔らかい。
My fingers are so flexible they bend backward.