[あいてにしない, aitenishinai] (exp, adj-i) to ignore; to take no notice of; to give the cold shoulder to; to not associate with; to snub; to refuse to deal with
[あいてにする, aitenisuru] (exp, vs-i) (See 相手にしない, 相手をする) to keep company; to listen to; to associate with; to take notice of; to deal with; to play against (e.g. a team); to take on (e.g. a rival)