Hypocrisy (nifaaq) according to islam is of two kinds.
The ideological one in the beliefs (for example you are against believers/mujahideen gaining victory and you are supporting the disbeliever enemies secretely or openly while you claim that you are a muslim, or you are against the shari'ah or you hate any aspect of islam) and the one in actions or speech.
The first one is worse and those people are worse then disbelievers, but when muslims sometimes sin, betray trusts, lie or do anything which a true beiiever should not do, they fall into the second category, hence it's sinful.
But the best thing is to refrain from all forms of nifaaq, that in the heart as well as in speech and actions. May Allah keep us away from nifaaq, the inner and the outer aspects of it, ameen.