Bellamy
nickname for you: Babe: there is no special reason behind this nickname, babe was just the first thing he called you or Reina/Rey (queen/king in spanish): since you call him Rey and he is the king, he calls you his queen/king.
nickname for him: Bell: only those closest to him call him Bell or Rey (king in Spanish): he was the king of The 100 and the Spanish language has always interested you both.
Clarke
nickname for her: Yin (Chinese for female force): she was a strong girl and you admired her for that or Princess: you called her that even before The 100 did.
nickname for you: Yonggan (Chinese for brave): she also thought you were very strong and she looked up to you for that or Baby Girl/Boy: there is no special meaning behind this nickname, it was just the first thing that popped into her head whenever she would see you.
Finn
nickname for him: Epaitsekas (Finnish for selfless): he always made sure you were taken care of first or Soldier: he always powered on and never let anything stop him from getting what he wants.
nickname for you: Valo (Finnish for light): you lit up his dark world and he is forever grateful to you for that or Majesty: he always believed you belonged to some royal family by the way you carried yourself.
Jasper
nickname for you: Dork: you always did goofy things to cheer him up or Prinzessin/Prinz (German for princess/prince): you always needed saving (but he didn't mind saving you).
nickname for him: Michael Jordan: it was just a silly nickname because his last name is also Jordan or Retter (German for savior): he was always there to save you from others or yourself.
Lincoln
nickname for him: Kipa Amani (Swahili for peace keeper): kind of self explanatory; he kept the peace for both the Trikru and Skaikru or Abraham: after the 16th president of the United States (he didn't understand this nickname until you explained it to him for the 20th time).
nickname for you: Mate Nafsi (Swahili for soul mate): he thought you guys were destined to meet since you fell from the sky or Asteria: the Greek Goddess of the stars so pretty self explanatory.
Monty
nickname for him: Atamai (Samoan for smart): this one is pretty self explanatory; Monty was raised in agriculture and practiced engineering, calling him smart is an understatement or Smart Ass: because he is smart and an ass sometimes.
nickname for you: Tulai Laufuga (Samoan for rose petal): because he thinks you are beautiful and delicate like one or Orchid: he thought it was the most beautiful flower he planted when he was in agriculture and so he named you after it.
Murphy
nickname for him: Sy Blue (Albanian for blue eyes): you were infatuated by his blue eyes because they changed to different hues depending on the lighting or Sass Master: because he is one most of the time.
nickname for you: Oqean (Albanian for ocean): you are as beautiful and mysterious as one or Lioness: you were as strong, caring and brave as one.
Octavia
nickname for her: Gerrari (Basque for warrior): because she's a bad ass, very brave and very strong or Love: you always associated her face with that word.
nickname for you: Topatu (Basque for found): she claims she found herself when she met you or Cutie: in her world, you were the cutest person she knew.
Raven
nickname for her: Ikaika (Hawaiian for strong): Raven has always been a strong girl throughout her whole life (especially when she hurt her leg) or Avifauna: the technical term for a bird since she was named after one.
nickname for you: Akua (Hawaiian for goddess/god): she always thought you carried yourself royally but with respect for others like a goddess/god or Sunshine: you always brightened up her day.
Wells
nickname for him: Speco (Esperanto for kind): he always put you and others before himself or JaJa: when you first met, you accidentally mispronounced his last name.
nickname for you: Bela (Esperanto for beautiful): he thought you were the most beautiful girl he had ever laid eyes on or Butterfly: you were as free and as beautiful as one.
**ok, this first started out with just Bellamy's preference having a nickname translated but then I kinda started liking the translations and everything and wow. & did you notice I used FINNish for Finn ;-) also, if any of my translations are wrong (I used google translate), please tell me! thank you**