Expressions (phrases, clauses, etc.), Ichidan verb
to set one's hand to; to start work on
いずれは手をつけなければならないだろう。I suppose I've got to get my feet wet sometime. to embezzle; to use (money obtained in illegal fashion)
to have sexual relations; to have an affair
Also written 手を付ける【てをつける】、手を着ける【てをつける】