Longlimbs have not canonically been seen yet, but they likely possess the same traits as longarms and longlegs (double-jointed long arms and long legs respectively).
Whole Cake Island Arc
One longlimb human was captured by Big Mom and trapped within a book full of different creatures by her son, Mont-d'Or. Big Mom showed it to the Vinsmokes along some of the other creatures in her collection.
Anime and Manga Differences
In the manga, when Big Mom showed the Vinsmokes the longlimb she had, only a speech bubble of it crying for help was shown. So nothing about its appearance and gender are known.
The anime depicted the longlimb as a man, giving him masculine limbs (the rest of his body was not shown) and a male voice actor. His arms did not appear to have the double-joints characteristic of the Longarm Tribe.
- The literal transition of longlimb humans is "Longarmleg Humans".
- They appear to be based on the Ashinaga-tenaga (足長手長 Long Legs Long Arms?), which are a pair of creatures, one of which has long arms and the other has long legs; the longlimb humans are thus a combination of the two.