Endeavoured adverbs are provided in this article. The words listed here are commonly found along with the verb endeavoured in sentences. This reference page helps answer the question what are some adverbs that describe or modify the verb ENDEAVOURED.
accordingly, anxiously, briefly, carefully, constantly
earnestly, especially, evidently, faithfully, formerly
frequently, honestly, immediately, lately, merely
naturally, really, repeatedly, simply, strenuously
studiously, successfully, unsuccessfully, vainly
Hope this word list had the endeavoured adverb you were looking for. In addition to adverbs used with endeavoured, other example verb adverb pairings can be found on this site.
You can help by adding more adverbs in the comments. Thanks.