two statements that are inconsistent cannot both be true [= contradictory; ≠ consistent]:
The accounts of the witnesses are inconsistent.
His results are inconsistent with our data.
not right according to a particular set of principles or standards [≠ consistent]
His conduct was inconsistent with what is expected of a Congressman.
inconsistent behaviour, work etc changes too often from good to bad [≠ consistent]:
The team's performance has been highly inconsistent this season.