noun
being completely occupied with; devoting oneself entirely to
Describes a state where one is so absorbed in a single task or person that they cannot attend to anything else. Often used with ~になる or ~だ.
最近、仕事にかかりきりで、家事が全然できていない。
Lately I've been completely tied up with work and haven't been able to do any housework at all.
母は病気の祖母にかかりきり
My mother is completely occupied with caring for my sick grandmother.
From the verb 掛かる (かかる, 'to be engaged in') + きり (from 切る, indicating a state of being completely in that condition).