Synonyms, words that have the same basic meaning, do not always have the same emotional meaning . For example, the words 'stingy' and 'frugal' both mean 'careful with money' . However, to call a person stingy is an insult, while the word frugal has a much more positive connotation .similarly, a person wants to be slender nut not skinny , and aggressive not pushy.
Therefore, you should be careful in choosing words because many so called synonyms are not really synonymous at all.