A synonym is a word with the same or a similar meaning as another word.
For example, the words big and large are synonyms. Buy and purchase are also synonyms – although we tend to use “buy” in a more informal context, and “purchase” in a more formal context.
Keep in mind that some synonyms in the list below might not be “perfect” synonyms – there may be slight differences in meaning and connotation. For example, the words smart and wise. Both of them mean “intelligent,” but the word wise also implies that the person has additional good judgement and deep perception about life.
Synonyms are often used in different collocations, too. For example, we can describe either a person or an idea as brilliant, but only a person can be astute.
Powerful, potent, and firm are synonyms for strong. A person with a strong voice can have a powerful voice, but not a potent voice. A strong alcoholic drink can be potent, but not firm.