However, "regret" is often used as a base for other words, and these can have suffixes:
* Regretful: This adjective describes someone who feels regret.
* Regrettably: This adverb expresses something done with regret.
* Regretted: This past participle describes something that has been regretted.
* Regretting: This present participle describes someone who is currently feeling regret.
* Regretfully: This adverb expresses something done with regret. (Similar to regrettably)
While these words all stem from "regret", they are formed with different suffixes to convey different meanings.