Mutual exclusivity (ME), the tendency to map novel words to unfamiliar referents, can support children’s word learning (e.g., Markman & Wachtel, 1988). A recent study (in prep) demonstrated that 4-year-old English-speaking children show a weaker ME effect for novel verbs than nouns, consistent with evidence that verbs are harder to learn (e.g., Gentner, 1982). Here, we replicated this study in adults. Adults viewed videos (verb trials) or static images (noun trials), one familiar and one unfamiliar, and selected the best match for a novel verb or noun. Adults applied ME for both verbs and nouns, but significantly less for verbs (z = 4.073, p = 0.0003). Adults also had longer reaction times (β = 471.25, p < 0.0001) and lower confidence ratings (β = -7.035, p < 0.0001) for verbs than nouns. Thus, less use of ME for verbs stems from something about event conceptualization rather than child development.