かりに
かりに · karini · JLPT N1 · adverb
temporarily
仮 (kari) = provisional, temporary; かりに = 仮 + に, so 'provisionally, let's say'
仮 means provisional or temporary, as in 仮定 (katei, a working assumption). Adding に turns it into a 'supposing that' stance, used when setting up a hypothetical for argument's sake.