Clue: Nit-picker to kiss and cuddle, adopting fighter's standard (6)
Answer: PEDANT
Explanation: Nit-picker to kiss and cuddle, adopting fighter's standard (6)
PET ("kiss and cuddle") "adopting" DAN ("fighter's standard") 
From WIkipedia – *In Judo, improvement and understanding of the art is denoted by a system of ranks split into kyu and **dan** grades.