Caesgender refers to being genderblind when considering one's own gender or the gender of others. A person who is caesgender will acknowledge the existence of gender and gender identity, but have never recognized it in themself or other people. For example, someone who is caesgender may be also agender because of a lack of identity with another gender.
The term originates from caesexual, coined by @creechercourse on Tumblr[1], and comes from the Latin word caecus, meaning blind.