Definition of nobbles:
(v) :
(UK, Ireland, slang) To gain influence over by corrupt means or intimidation.
(v) :
(UK, Ireland, Commonwealth, slang) To injure or obstruct intentionally.
(v) :
(UK, Ireland, slang) To steal.
(v) :
(transitive, slang) To tamper with (typically a racehorse or greyhound) in order to prevent it from winning a race.
(n) :
(UK, slang) A deliberate act of injury or obstruction.