Title. What is the difference between these tags? Judging by the wikis, they seem to be representing the same concept, a character with a head but no face.

faceless / featureless_face

faceless_character is at the top of the suggested tags when typing faceless, so I think it'd be better to alias faceless away, or maybe disambiguate, assuming there's no difference between faceless and featureless_face. faceless might need to be manually combed through to see what's faceless_character and what's featureless_face

Side note, does it count as faceless_character if a small part of the character's face is visible? Say, only their mouth, or only their chin.

Alias it to a disambiguation.

The bulk update request #8989 is pending approval.

create alias faceless (1340) -> faceless_(disambiguation) (0) # has blocking transitive relationships, cannot be applied through BUR

Reason: faceless_character and all the other faceless_*form* tags are at the top of the suggested tags when typing faceless, but the wiki for faceless indicates it's supposed to be used like featureless_face, and looking through the listing for faceless it's clear that some entries should have been tagged faceless_character instead. Disambiguation should help make sure these entries are properly tagged.

EDIT: See also topic #38675 and BUR #4881
no_face needs to be removed as an alias to faceless before this can go through.