だって
だって · datte · JLPT N3 · conjunction
because
だって = だ (it is) + って (so they say): 'but it is!', the classic excuse
It's the copula だ plus the quoting particle って, so it literally means 'saying it is'. Children whine だって! when they mean 'but…!' or 'because…!'. After a noun it means even, as in 子供だって (even a child).