Greenhorn
Part of speech: noun
Definition: an inexperienced person; a novice, beginner or newcomer
Rookie
Part of speech: adjective
Definition: non-professional; amateur
Part of speech: noun
Definition: An inexperienced recruit, especially in the police or armed forces.A novice.An athlete either new to the sport or to a team or in his first year of professional competition, especially said of baseball, basketball, hockey and American football players.A type of firecracker, used by farmers to scare rooks.
Example sentence: I've heard this stuff about a kicker 'losing his leg' ever since I was a rookie, and I can tell you that there is nothing to it. Every time a field goal kicker misses a few, the word gets around that he's lost his leg, meaning his kicking strength.