1 that protects sb/sth from attack 防御的: The troops took up a defensive position.部队采取守势。 [OPP] offensive 反义词为offensive
2 showing that you feel that sb is criticizing you. （感到被批评时）采取守势: When I asked him about his new job, he became very defensive and tried to change the subject.当我问及他的新工作时，他躲躲闪闪不肯多说，而且企图改变话题。
defensive²
/dɪˈfensɪv ||; dɪˈfɛnsɪv/nounon the defensive acting in a way that shows that you expect sb to attack or criticize you 采取防御姿态；采取守势: My questions about her past immediately put her on the defensive.一听到我问她过去的事时，她马上采取守势。