"Underlook" is a relatively uncommon word that can be substituted with a handful of synonyms to capture its essence. One suitable alternative is "neglect", which implies the act of inadvertently overlooking or disregarding something or someone. Another synonym is "ignore", which signifies choosing not to pay attention or give importance to a particular matter or individual. Similarly, "overpass" can be used in contexts where one fails to acknowledge or recognize the significance of something or someone. Other potential synonyms for "underlook" include "disregard", "unheeded", and "brush aside". These words offer alternative ways to describe the act of not giving due consideration or attention to a particular subject.