Sidharth is a synonym for one who mopes, cries and grumbles all the time. AND can be ruthless,cruel and a sadist.
Example 1 : Baccha, Stay away from a Sidharth. He might push you into depression and eventually suicide.
Example 2:person1: Once I saw a grumpus staring at me, oh it was a fearful sight to see.
person 2: Rubbish, that was'nt a grumpus it was a siddharth.