The crossword clue "about to discover" commonly has the answer "ONTO," which is a 4-letter word meaning "about to discover (something secret)" or "aware of".
Other possible synonyms related to "discover" in crossword puzzles include words like FIND, ESPY, LEARN, DETECT, UNEARTH, and UNCOVER, depending on the number of letters and context. However, specifically for the phrase "about to discover," the best fitting answer is "ONTO," especially when the clue indicates 4 letters.