Having no eyelids or being without the ability to blink.
From Greek a- (without) + blephara (eyelids). This medical/biological term literally means lacking the paired membranes that cover and protect the eyes.
Some cave fish and certain reptiles are ablepharous—and this trait actually tells us how evolution works: when creatures live in darkness for millions of years, maintaining expensive body parts like eyelids becomes wasteful, so they disappear!
Complete word intelligence in one call. Free tier — 50 lookups/day.