Q: Is threat a conduct according to section 8 of evidence act ?

Ans: Conduct is a behaviour and can be in oral, written, or gestural form. Threat is a previous conduct. 

The conduct is of two types, i.e., previous conduct as well as subsequent conduct. Eg: The threat to murder is previous conduct. The attempt to commit an offence is also previous conduct.  Such conduct is relevant u/s 8 of the Evidence Act, 1872.