tangential
adjective uk/tænˈdʒen.ʃəl/ us/tænˈdʒen.ʃəl/
(OF TANGENT)
mathematics specialized切线的;正切的
of or along a tangent
(INDIRECT)
（主题或活动）离题的，不相关的
(of a subject or activity) different from or not directly connected with the one you are talking about or doing
a tangential issue 一个不直接相关的问题