faltar
/falˈtaɾ/ · A2 · verb
to be lacking, to lack, to not have
🧩 faltar = fault + -ar: where there is a fault, something is lacking
From Latin fallere (to fail, to deceive), the same root as English fault, fail and false. A fault is a gap, so faltar means to be missing or still left to go: me falta tiempo = time is lacking to me, I am short of time.