'刚才' (gāng cái) is an adverb meaning 'just now' — referring to a very recent point in the past, usually within the last few minutes. Though it looks like two separate characters, 刚 and 才, together they form a fixed compound with a single grammatical function. '刚' emphasizes immediacy or freshness of timing, while '才' adds a nuance of recency or newness — not 'only' or 'just' in the sense of limitation, but 'only just now.' The two characters are inseparable in this usage; you cannot omit one or rearrange them.

This word commonly appears before verbs to indicate that an action was completed moments ago. It often co-occurs with perfective aspect markers like 了 (le), though 了 is optional when the context makes completion clear. '刚才' can also stand alone as a time noun ('a moment ago'), but its most frequent and natural use is adverbial, modifying the verb phrase. It’s neutral in register — appropriate in both spoken and written Chinese, from casual conversation to formal reports.