adjective
always used before a noun :defending or protecting someone or something from attack :helping to keep a person or thing safe
[more ~; most ~] :behaving in a way that shows that you feel people are criticizing you
always used before a noun sports :of or relating to the way that players try to stop an opponent from scoring in a game or contest
noun
on/onto the defensive
in or into a situation in which you are forced to defend or protect someone or something
in or into a position in which you have to argue that something (such as one of your actions or beliefs) is good or correct when others say that it is bad or wrong