Do you have malapropisms that really get on your nerves? Ones that stand out in any text you read, in any words you hear, and grate? I do.
I dislike the expression "quantum leap" when it's used to refer to a particularly large (conceptual) jump; a quantum leap is the smallest conceivable leap.
Worse than this is "significant", used in the same sense, as "large" or "noteworthy". A difference being significant means it is statistically distinguishable, i.e. unlikely to be an artifact of random chance. Significance has nothing to do with effect size: a small difference can be significant, and a large difference insignificant. (In fact, one must take further care to confuse significance with semantic meaningfulness. As sample sizes increase, any difference, no matter how small, will become significant, but whether this tells you anything is another matter.)
Turning to German there's "anscheinend" and "scheinbar", a pair of words that both mean "seemingly", but with different twists. The former indicates that appearance and reality match; the latter, that they don't. Wilhelm Busch, for instance, wrote: "Scheinbar schlummert der Leib, aber die Seele ist wach": Silen appears to be sleeping, but really isn't. Some people I know consistently (at least they are consistent!) use "scheinbar" when they mean "anscheinend", and it's always bugging me something severe.
EDIT, 2019-01-07: if you're looking for an alternative to "significant", perhaps consider "substantial". Also, here's another English pair: "effective" and "efficient"; though these are not wholly dissimilar in meaning, I've found that people tend to say "effective" even when they really mean "efficient" (but not, as a rule, vice versa).