The
阿 (Ā) prefix is a colloquial / southern way of forming nicknames - pin it onto any single character of someone's name (typically the last) to get an affectionate form:
阿吉,
阿明,
阿强. Especially common in Cantonese-speaking and Taiwanese contexts.
阿吉 is also an old word for distilled liquor (
烧酒).
