56 synonyms for doing such as doodad, accomplishment, dingus, and doobry. Doing is a noun, and its antonyms are stopping and ceasing.
Accomplishment, achievement, acquittal, act, action, activity, behaviour, bringing off, caper, carrying out, completing, completion, conduct, deed, discharge, discharging, effecting, effectuation, endeavour, enterprise, execution, exploit, feat, handiwork, implementation, implementing, performance, performing, pulling off, realization, undertaking, venture, and work.
Dingus, doobry, doodad, doodah, doofer, doohickey, doojigger, gizmo, gubbins, hootenanny, oojah, oojamaflip, thing, thingamabob, thingamajig, thingo, thingummy, what's-its-name, what-d'you-call-it, whatever it is (called), whatnot, and whatsit.