The Spanish word 'gastador' (meaning 'spender') comes from combining the verb 'gastar' ('to spend') with the agent suffix '-dor'. The verb 'gastar' itself derives from the Latin word 'vastare', meaning 'to devastate' or 'lay waste to'. Over time, the meaning evolved from destruction or devastation to the more general concept of using up resources or spending money. The suffix '-dor' is added to verbs to create nouns that describe someone who performs that action, similar to how '-er' works in English words like 'worker' or 'teacher'.

The initial 'v' in Latin 'vastare' changed to 'g' in Spanish 'gastar', which is a common sound change in the development from Latin to Spanish. This transformation of both sound and meaning - from devastating or laying waste to simply spending - shows how words can evolve to take on more moderate or general meanings over time.

Some related Spanish words include the common verb 'gastar' (to spend), 'gasto' (expense), and 'gastos' (expenses). These all share the same Latin root 'vastare' and form a family of words related to spending and expenses.

While not directly cognate, the English word 'waste' is distantly related, as it also comes from Latin 'vastare'. This connection makes sense when you think about how spending money could be seen as using up or 'wasting' resources. The English word 'vast' is also related, originally referring to something empty or devastated, though it now means extremely large or extensive.