• 生徒せいと — student
• 教徒きょうと — believer / adherent
• 徒歩とほ — on foot
• 徒労とろう — fruitless effort
• 信徒しんと — follower (of a religion)

Originally associated with walking or traveling on foot, 徒 came to symbolize those who follow, such as disciples or students. It also acquired abstract meanings like futility or emptiness — seen in words like 徒然つれづれ (idleness, boredom) and 徒労とろう.

彼かれは優秀ゆうしゅうな生徒せいとです。
He is an excellent student.

毎日まいにち学校がっこうまで徒歩とほで通かよっています。
I walk to school every day.

努力どりょくが徒労とろうに終おわりました。
My effort ended in vain.