Capicitor

The word you want is capacitor. Your question is incoherent in English. You should ask: "Why does a capacitor resist (not oppose) voltage?"

A capacitor temporarily stores an electrical charge. The capacitor will "resist" the current when it holds its maximum charge. At such time as it discharges the electrical charge it has built up, it will allow the current to flow until it once more holds its maximum charge.

Set's right A32 but if you're still unsure I like to chat too