godan verb (-ru), intransitive verb
Describes leaning one's body or weight against something for support; often used casually. The kana form よっかかる is standard.
彼は壁に寄っかかって立っていた。
He was standing leaning against the wall.
疲れたので、ソファに寄っかかった。
I was tired, so I leaned back on the sofa.