一日不如一日

to be getting worse by the day

one / single / a (article) / as soon as / entire; whole; all; throughout / "one" radical in Chinese characters (Kangxi radical 1) / also pr. [yao1] for greater clarity when spelling out numbers digit by digit

abbr. for 日本[Ri4 ben3], Japan

sun / day / date, day of the month

no; not so / (bound form) not; un-

not equal to / not as good as / inferior to / it would be better to

as / as if / such as

consistent / the same / unvarying