The word 'unearth' is a straightforward combination of the Old English prefix 'un-' and the noun 'earth'. The prefix 'un-' carries the sense of reversing an action or state, while 'earth' refers to the soil or ground. Literally, the compound meant to remove from the earth or bring out of the ground. Over time, this literal meaning of digging something up broadened metaphorically to encompass the act of discovering or bringing to light anything that was hidden, buried, or forgotten, not just physical objects. This semantic extension from a physical to a figurative act of revelation is a common pattern in English word development.

Structure: un (reversal) + earth (ground) un- (a prefix of Old English origin, indicating reversal or deprivation); earth (a noun of Old English origin, meaning soil, ground, or the world)