The word 'under lain' refers to something that has been buried beneath or placed below the surface. Antonyms for this term may include words that describe things that are above or on top of the surface, such as 'overlaid', 'superimposed', 'exposed', or 'visible'. Other antonyms may describe situations where nothing is being concealed or hidden, such as 'open', 'unburied', 'uncovered', or 'unveiled'. Alternatively, the antonyms could describe something that has been removed or extracted from beneath the surface, such as 'dug up', 'unearthed', or 'extricated'. Overall, antonyms for 'under lain' describe concepts and physical objects that are dissimilar to those which are hidden or covered beneath the surface.