GRE Sample Test 1 Verbal Reasoning 2

Try working with the second blank first. The clues are that the fashions were “considered daring” and then “imitated.” Starting with the second blank, the sentence suggests that the fashions have changed from what they once were—in other words, daring.
Outlandish is a good synonym for daring and it makes sense that, in the first blank, the fashions were original and then lost their impact because of excess imitation.