A good deed is an action you take for the betterment of another person or society as a whole. However, good deeds need to be perceived as good even if the intent is positive.
What is good deed in Islam?
Doing a deed and doing deed with good intention are separate things. The intention that doing this deed will reward a Muslim with virtues and help attaining the mercy of Allah in this dunya and afterwards then this surely is a base that Allah will accept the deed and will reward accordingly.
What would you define as good deeds and good words?
Good words: those thought forms expressed verbally. Good deeds: those words followed or accompanied by the actions.