To the novice, "to the untrained eye" might sound like a phrase that cannot be replaced by any other. However, there are several synonyms that can be used interchangeably with this expression. For instance, "at first glance," "superficially," and "on the surface" can all substitute the phrase "to the untrained eye." Similarly, one can also use "initially," "at a first blush," or "apparently" to convey the same meaning. Alternatively, depending on the context, one can use "seemingly," "ostensibly," or "outwardly" as synonyms for "to the untrained eye." All of these phrases emphasize a lack of depth of understanding or experience in a particular subject or situation, leading to an initial perception that may not be accurate.