croitor, croitoreasă = tailor (not accepted by DL - I reported it)
according to wiktionary, seamster (seamstress) means ”A person who sews clothes professionally”. That would be in Romanian ”cusător, cusătoreasă”
My answer "The clothes of the dressmaker are green." was marked as incorrect. I think that you would be hard put to find a seamstress in the western world nowadays but there are are still dressmakers around. At the very least both words should be acceptable.