The word 刚才 is formed by combining two characters that both individually carry meanings related to recent time or immediacy. 刚 (gāng) on its own can mean "just" or "a short while ago", while 才 (cái) also conveys a sense of "just now" or "only then". Their combination creates a single, reinforced temporal concept where the similar meanings merge and strengthen each other to specifically denote "a moment ago" or "just now", effectively forming a compound word through the synergy of its nearly synonymous components.