significant

important in effect or meaning; "a significant change in tax laws"; "a significant change in the Constitution"; "a significant contribution"; "significant details"; "statistically significant"

fairly large; "won by a substantial margin"

too closely correlated to be attributed to chance and therefore indicating a systematic relation; "the interaction effect is significant at the .01 level"; "no significant difference was found"

rich in significance or implication; "a meaning look"