Nictitation is the medical term meaning the involuntary closure of the eyelids or a wink. It can be considered a difficult word to pronounce and spell, so here are some synonyms that can be used in place of nictitation: blink, flutter, flicker, twinkle, or wink. These words can be used interchangeably depending on the context or tone of the conversation. For example, blink may be too casual for a medical discussion, while flutter seems more appropriate. In any case, using synonyms can help avoid repetition and make your writing or speech more interesting and varied.