IPA: /ˈbɪl.dʌp/
KK: /ˈbɪlˌdʌp/
The process of gradually increasing or accumulating something, such as tension, resources, or praise.
There was a significant buildup of tension before the announcement was made.
Buildup → It is formed from "build" (from Old English "byldan", meaning to construct or create) and "up" (meaning to a higher position or level). The word "buildup" refers to the process of constructing or accumulating something to a higher level or intensity.
Think of the act of 'constructing' ('build') something to a 'higher level' ('up') — that's what buildup means.
No commonly confused words.