A nameclaim is a type of claim where the player simply gives the flavor name of their role. The player does not mention their role's abilities or any results they may have.
Because a player's flavor name may hint at whether they are a good power role, this is not employed very often unless it is thought that simply knowing players' names can give the Town an advantage. For instance, if it is thought that the scum have no falseclaims or poor safeclaims, a nameclaim can potentially pressure the scum into claiming their real role name or their poorly-fitting (un)safeclaims.
Alternatively, a nameclaim can cause responsibility for actions related to particular roles' flavor to be pinned on the appropriate players. This is a good idea in games where a role's flavor has no bearing on whether they may be a power role.
Nameclaims are frowned upon in many places, though, since they can skew the balance too much toward town - the game will be won by lynching people with less believable nameclaims rather than scumhunting. For example, in a Star Wars themed game, the people who claim Luke Skywalker, Princess Leia, Han Solo, Yoda, Chewbacca, etc would be treated as confirmed, while someone who claims Momaw Nadon would be lynched. This would require the Mafia to research the flavor to create a believable fakeclaim, which could still be counterclaimed.