抑 is a bound form (不成词语素) that only appears as part of compound words, never alone in modern Chinese. It has two distinct functions: (1) as a verb root meaning 'to suppress, restrain, or curb', seen in words like 抑制 (yìzhì, to inhibit) and 压抑 (yāyì, to feel oppressed/depressed); (2) as a literary conjunction meaning 'or' or 'but', used in 抑或 (yìhuò, rather...or). The meaning depends entirely on the compound it forms.