This is the 8179th most frequent Polish word.
olej
Oil.
In this sentence, 'olej' refers to cooking oil or another type of oil that one might purchase at a store.
Kup olej w sklepie.
Buy oil at the store.
Here, 'olej', in its verb form 'olewaj', is used colloquially to mean 'to disregard or neglect' someone or something.
Nie olewaj swoich obowiązków!
Don't neglect your duties!
In this context, 'oleju' (the genitive form of 'olej') refers to engine oil, essential for machinery operation.