The Spanish verb 'anegar' (meaning 'to flood' or 'to drown') comes from the Latin word 'enecare', which meant 'to kill completely'. This Latin word was formed by combining the prefix 'e-' (meaning 'out') with 'necare' (meaning 'to kill', especially without weapons). The root 'necare' itself derives from the Latin noun 'nex', which referred specifically to death without bloodshed.

The semantic evolution from 'to kill completely' to 'to flood/drown' makes intuitive sense, as drowning is a form of death without weapons or bloodshed. Over time, the meaning became more specifically associated with death or destruction by water.

A related Spanish word is 'negar' (to deny or negate), which comes from the same Latin root 'necare'. While 'anegar' developed to mean physical destruction by water, 'negar' took on the metaphorical sense of nullifying or killing off an idea or statement.

English speakers might recognize the connection to words like 'necrology' (a list of deaths), 'necropolis' (city of the dead), and 'necromancy' (divination through communication with the dead), which all contain the same ancient root related to death. The word 'noxious' (harmful or poisonous) is also distantly related, coming from the same Indo-European root.