Antonyms means opposites. Not all words have opposites, and advertising is one of them. You can't anti-advertise. The most you can do is not to advertise.
If pushed, I suppose one could consider "camouflage" or "hide" as opposites to advertise.
Sell, sale, auction, peddle, or advertise. Those are opposites of purchase.
If you mean by 'advertise' to make public/proclaim/boast... then antonyms (opposite words) might be conceal, withhold, depricate. However there is no antonym for advertise in terms of its commercial use.
Antonyms
antonyms
What are the antonyms for cavernous
what isbrief of antonyms
antonyms
antonyms
antonyms
antonyms for slender
Antonyms
yes antonyms are opposite