Am surprised people are debating what a swordsman is, whether Kizaru and Bm are swordsmen etc. The definition of swordsman and what a sword is have already been defined in the manga.
- Someone who uses a sword is a swordsman.
Look at the panel below.
Vergo says he will cut Luffy and co
to ribbons then
he realises he can't see his sword.
Monet replays to this that
Vergo is not a swordsman. (Implying only a swordsman uses a sword)
Vergo then replys that
he is indeed not a swordsman. Then he states that he will crush Luffy and co. (He then changes his mind from cutting Luffy and co to crushing them since he is not a swordsman thus he can't cut them.)
If you follow this conversation it is clear that
to be a swordsman all you need is to
fight with a sword. From
Monets words it is clear that a swordsman fights with a sword. Therefore a
person that isn't a swordsman will not fight with a sword. As a result, it is not strange that Vergo who is not a swordsman doesn't have a sword.
- A physical sword is not needed to be a swordsman. Anything can be a sword so long as the user defines them as such. Including the users body
Kaku is a 4 swordstyle user depsite only having 2 physical swords. He uses his body as swords and later uses his nose as a sword when he gets his df.
Zoro thought of Kaku as a 2 sword style swordsman, however, Kaku corrected him and said he is infact a 4 swordstyle swordsman. Zoro follows by stating that Kaku's body is a weapon.
- Zoro: "If it is swords, am all for it"
To Zoro, if you use a sword, you are a swordsman, be it a real sword, or one made from an ability, your legs etc
- Zoro: "Anyone that calls themself a swordman"
Anyone that calls themself a swordsman is a swordsman to Zoro.
tl;drThe manga is very clear on who a swordsman is and what a sword is. If an individual meets any of the criteria identified above, they are a swordman.
Kizaru used a sword made from his df whilst BM also used a sword made using her df. This still count as swords. If legs (Kaku) are swords, then Kizaru and Bm's swords made with their dfs are definetly swords.
Therefore Kizaru and BM are swordsmen