Often used in negative constructions like 見境なく or 見境がない to mean 'indiscriminately' or 'without distinction'. Implies a lack of careful judgment or differentiation.
I was so hungry that I ate everything without distinction.
recklessly; without considering the consequences; going overboard
Etymology
Compound of 見 (mi, 'seeing') and 境 (sakai, 'boundary'). Literally 'seeing boundary', it refers to the ability to draw a line or make a distinction based on what one sees or perceives.