Outnumbered adverbs are provided in this article. The words listed here are commonly found along with the verb outnumbered in sentences. This reference page helps answer the question what are some adverbs that describe or modify the verb OUTNUMBERED.
actually, badly, clearly
completely, considerably, easily
greatly, heavily, hopelessly
largely, overwhelmingly, seriously
severely, significantly, slightly
usually, vastly
Hope this word list had the outnumbered adverb you were looking for. In addition to adverbs used with outnumbered, other example verb adverb pairings can be found on this site.
You can help by adding more adverbs in the comments. Thanks.