This molecule is polar. This is because the oxygen-carbon dipoles do not cancel, which means the electrons are not evenly distributed. So, there is a higher electron density centered on the oxygen atom, which makes it partial negative, and there is a lower electron density region near the hydrogen atoms (further away from the oxygen), which makes it partial positive. When there are partial positive and partial negative regions, there is a dipole, which makes it polar. Below is the Lewis structure of diethyl ether (C4H10O):