The Spanish verb 'sudar' (to sweat) comes directly from the Latin verb 'sudare', which also meant 'to sweat'. This is a straightforward inheritance where both the form and meaning have remained remarkably stable from Latin to modern Spanish.

Some related Spanish words include 'sudor' (sweat), 'sudoroso' (sweaty), and 'sudadera' (sweatshirt). All these words share the same Latin root and form a family of words related to sweating and perspiration.

While English 'sweat' comes from a different Germanic root, we do have some English words related to Spanish 'sudar' through the Latin root. These include 'sudorific' (causing sweat), 'exude' (to ooze out, originally referring to sweating), and 'transude' (to pass through as a fluid). The medical term 'sudoriferous' (sweat-producing) is another example, though these English cognates tend to be more technical or medical terms rather than everyday vocabulary.