Adjectives

(a)punctual, on timeacting or arriving or performed exactly at the time appointed“she expected guests to be punctual at meals”, “he is not a particularly punctual person”, “punctual payment”, “she is always on time for class”
(s)on timepayable in installments within a designated period of time“we were short of cash, so we purchased our refrigerator on time”

Adverbs

(r)on time, punctuallyat the expected or proper time“she always arrives on time”