I once found a word I really liked, but forgot, this was a word used to describe a person who pretends not knowing or being incapable of understanding certain information in order to avoid a presumed commitment.
For example, A mother may want one of two children (A & B) to clean 'the room', so she asks child B "Has your brother (A) cleaned the room?". So the audacious child B "responds I don't know", because he assumes that if he answers "no" (which is in fact the case), then he knows that he will be told to clean it.
In short, it is basically a word that describes a person who purposefully feigns ignorance for the ulterior motive of being negligent/lazy.
Thanks.