the.com/responsiveness

means The quality of reacting or replying promptly and appropriately to something, rather than leaving it hanging.

from Built from 'respond,' which traces back to Latin 'respondere' — 're-' (back) plus 'spondere' (to pledge or promise). To respond was originally to make a pledge in return for one received, like answering a vow with a vow. The '-ive' and '-ness' suffixes turned the act into a trait: not just the ability to answer back, but a settled character of doing so readily.