Nemu is derived from "nemuri" (眠り,"nemuri"?), which means "sleep" in Japanese.
Strengths and Weaknesses
This fruit's only power, as demonstrated by Noko, can put an opponent to sleep through hypnosis. With the seahorse flute's power to manipulate memories, the fruit can become much more powerful.
In the games, it was stated that to use this power, Noko must first blow his flute to activate his powers.
This fruit does not seem to have any specific weaknesses, and even more so, he is not affected by the Devil Fruit users' usual weakness of not being able to swim. The reason for this is never made clear though.
Noko mainly uses this power to put his opponents to sleep and absorb other
peoples' dreams and to take control of people. However it is shown that if he is hit the memories will start spilling out of his body and back into those to whom they belonged. He also turns down the food Zoe offers him, saying he eats left over memories.
This fruit is similar to the canon Memo Memo no Mi, as both has the ability to steal a person's memories.