In ancient times taking off one's shoes was a mark of respect.
Tips
usage
跣 is literary for 'barefoot', usually in 跣足 ('bare-footed'). The everyday word is 赤脚. In old ritual, going barefoot before a superior showed humility and respect.
足 is the foot radical, here written in its compressed left-side form. It points straight at the meaning: something to do with the feet, here bare ones.
