引信

引信	yǐn xìn	fuze; detonator
引	yǐn	to draw (e.g. a bow) / to pull / to stretch sth / to extend / to lengthen / to involve or implicate in / to attract / to lead / to guide / to leave / to provide evidence or justification for / old unit of distance equal to 10 丈, one-thirtieth of a km or 33.33 meters
信	xìn	letter / mail / CL:封 / to trust / to believe / to profess faith in / truthful / confidence / trust / at will / at random