IPA: /ˌæntɪˈklaɪmæktɪkəl/
KK: /æntɪˈklaɪmæktɪkəl/
Describing a situation where something is less exciting or impressive than expected, often after a buildup of anticipation.
The movie's ending was anticlimactical, leaving the audience disappointed after the thrilling buildup.
Anticlimactical is formed from "anti-" (meaning against) and "climax" (from Greek "klimax", meaning ladder or a point of highest intensity). The suffix "-ical" (meaning pertaining to) indicates that it relates to the concept of climax. Thus, anticlimactical refers to something that is against or contrary to a climax, often describing a disappointing or unsatisfying conclusion.
Think of 'anti-' meaning against and 'climax' as the peak or high point — so anticlimactical describes something that goes against the expected high point, leading to a letdown.