It is adj and verb. As adj means tortuous. For example, the mountain is very tortuous. As verb, means circle the behind or side.
My English is poor, I am very sorry about that. Maybe There are a lot of grammatical mistakes, but I hope you can understand 迂回.
迂回词性有两种,一做形容词回旋的意思,二做动词是绕到敌人侧面或后面。