Outstripped is a term that generally means to surpass or exceed expectations. There are several different synonyms that can be used to replace this term in order to convey the same overall message. One possible alternative is to use the term "surpassed", which is fairly similar in meaning and conveys the idea that one is exceeding a certain benchmark. Another option might be to use the term "surged", which suggests a rapid or sudden increase in performance or success. Other possible synonyms for outstripped might include "outran", "outdid", "outshone", or "outperformed", depending on the context and intended meaning of the sentence.