Sexual abuse without an abuser: For example, a person with severe learning difficulties might act in ways that sexually abused another without being a sexual abuser, because he or she was unaware that the other person was not a willing participant in the sexual activity in question.

A sexual abuser whose actions do not involve the experience of sexual abuse:  Consider, for example, a situation in which a dreadful person abused another sexually by making use of that person in a depersonalised way for sexual purposes, without their consent (because for example, in the case of a person with very severe learning disabilitis, they were unable to understand enough to be able to consent). The protagonist in such a situation would clearly be a sexual abuser, even if that other tolerated the activity (or even enjoyed it) without its being the case that the other  was sexually abused, at least in the sense of having experienced what hapned to them as abusive.

So could there be bullying without a bully? (And could there be a bully without bullying?)