I've encountered this phrase online and couldn't find a dictionary definition for the phrase. What does "rank dishonesty" mean, and especially what does the word "rank" mean in this context?
According to a dictionary, 'rank' means 'unpleasant', 'strongly', or 'extremely' which are different from each other but all make sense in this context. I want to first confirm if this is a set phrase that has a idiomatic meaning beyond the literal one. Secondly, if it is not a set phrase, which meaning of 'rank' is the right one here?
(My first impression, which is very likely wrong, is it means someone with lower social/military rank being deliberately dishonest (backstabbing) against someone with a higher rank.)