capable:
incompetent,
clumsy,
weak,
green,
ineffective,
impotent,
inept,
powerless,
inadequate,
unsuitable,
ignorant,
unqualified,
unintelligent,
stupid,
unskillful,
useless,
incapable,
untalented,
inexperienced,
inefficient,
unable,
unskilled.
experienced:
unfamiliar,
unknowledgeable,
unsophisticated,
immature,
untrained,
unseasoned, amateur.