Why would it be difficult to decide weather or not an element was a metalloid?

Deciding whether an element is a metalloid can be challenging because the properties of metalloids often overlap with those of metals and nonmetals, leading to ambiguity. Additionally, the classification can vary based on the specific criteria used, such as electrical conductivity, malleability, and chemical behavior. Furthermore, some elements exhibit different characteristics under varying conditions, complicating their classification. Therefore, consensus on defining metalloids can differ among scientists and sources.