“Locked in” is a slang expression that means someone is 100% focused on and committed to something, from a personal goal to a romantic relationship. Read on, because we’ll cover all of the meanings, how to use "locked in," and its definition outside of internet slang—plus similar slang phrases. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.