Pitiful means pathetic. If you don't even study for your test, you're making a pretty pitiful effort to do well.
The word pitiful can be used in a range of contexts. Most commonly, you'll see it used as an expression of contempt and pity, the way the word pathetic might be used. You might also see it used in reference to something unfortunate or deserving of pity — like a homeless mother and her child, begging for money on the street. Something pitiful might also be something very small or inadequate. A pitiful attempt, is one that isn't good enough.