Most often appears in fixed phrases:
一目了然 (yīmùliǎorán, "clear at a single glance") and
心中了然 (xīnzhōng liǎorán, "already clear in one's mind"). The character
然 here functions as a literary suffix meaning "...-ly / in a ... state," the same as in
显然,
突然,
必然. Variant form
瞭然 means the same.
