Ga-ga is a colloquial term used to express excitement or enthusiasm towards something or someone. There are several words that can be used as synonyms for ga-ga, such as infatuated, smitten, enamored, besotted, and in love. These words convey a similar level of excitement and attachment towards another person or thing. Other terms that could be used as synonyms for ga-ga include head-over-heels, crazy about, obsessed, or devoted. These words are commonly used in everyday language to express a strong feeling of admiration or affection, particularly towards a romantic interest or celebrity crush.