To covet something is to want it very strongly — and the point is that it already belongs to someone else. You do not just like it; you hunger to have it for yourself. It is a heavier, more formal word than want, and it often carries a moral warning: this kind of wanting is ugly or dangerous. English speakers know it from the Bible (Thou shalt not covet), so it can sound churchy or old. You might covet a neighbour's house, a friend's job, or someone's looks. Though actually, people stretch it in a lighter, almost joking way (I covet those shoes), but the core idea is still wanting what is not yours. It is not quite the same as envy: envy is minding that they have it; covet is wanting to take it.