Changing Minds defines passive behavior as avoiding what is truly meant and putting others' preferences before your own needs. Passive behavior is also connected with submissive behavior as both passive and submissive people tend to give others authority over themselves.
According to Changing Minds, a common example of passive behavior is to direct blame internally rather than toward external factors responsible for a given situation. Passive behavior draws criticism and shies away from any kind of conflict, often leading to false acceptance of blame when another person goes on the offensive. Changing Minds also explains that passive behavior goes along with vague speech that is intended to obscure in flowery language that is less likely to offend anyone.
Cognitive Behaviour Therapy explains that passive behavior involves a failure to express wants, needs or feelings. If those things are communicated, it is generally done in a very indirect and often apologetic way. The website also explains that passive people are merely responders to things and people in their environment rather than active decision-makers who take are willing to take direct control. Cognitive Behaviour Therapy explains that passive behavior is generally guilt-driven and geared toward never having to directly offend someone or tell them no.