If something is pettifogging, it is too concerned with tiny, unimportant details — often in a cheap or not-quite-honest way, like arguing about a comma to dodge the real point. It is a rather old, bookish, scornful word; you are more likely to read it than to hear a young person say it. Though actually, it first stuck to a kind of small-time lawyer (a pettifogger) who fought over scraps; today the adjective can describe any hair-splitting behaviour, in court or out of it.