"Assertive" and "aggressive" may seem like synonyms, but they are distinct words that differ in the nuances of their respective definitions.
"Assertiveness" refers to an attitude of confidence, boldness, or self-assurance. When someone is "assertive", he or she is free to pursue goals without fear of self-doubt or self-sabotage. It is more of an internal state than an action against .
one's environment. "Aggressiveness", on the other hand, refers to the more severe imposition of one's will on his or her environment.
While aggressiveness is not always a bad thing, the word carries an added connotation of severity. Acts of malice and violence are seldom ascribed to "assertiveness", more often they are ascribed to "aggressiveness". In this context, assertiveness means a more tempered, healthy attitude that no-holds-barred aggressiveness.
More Reference Links: http://www.merriam-webster.com/medical/aggressive http://www.merriam-webster.com/dictionary/assertive
