There are many synonyms that can be used to replace the phrase "was lost." Some options include "went missing," "disappeared," "vanished," "strayed," "wandered off," "got misplaced," and "went astray." Each of these synonyms conveys a slightly different nuance of meaning, but they all refer to the same general concept of something or someone being lost. These synonyms can be used interchangeably depending on the context in which they are being used, and can help to add variety and interest to your writing. When looking for alternative ways to say "was lost," consider which synonym best fits the tone and meaning you are trying to convey.