The verb 'thaw' originates from the Old English 'þāwian' (to melt, dissolve, become liquid), which is derived from the Proto-Germanic 'thawōną'. This, in turn, can be traced back to the Proto-Indo-European root 'tā-', meaning 'to melt, flow', which is also the source for words like 'thaw' and 'teem'. The core semantic logic has remained remarkably consistent from its ancient roots to modern usage: the transition from a solid, frozen state to a liquid or softer state due to heat. The addition of the '-ing' suffix creates the noun form describing the process itself or the present participle form of the verb, maintaining this fundamental concept of melting or loosening, whether applied literally to ice or metaphorically to formal relations.

The word 'thaw' is a simplex word of Old English origin. The '-ing' suffix is a modern English inflectional suffix (from Old English '-ung', '-ing') used to form the present participle or a verbal noun.