Heck/hek/ Definition 1 of 3Pro Tip 1/3Express Mildness Used to soften a statement, sound less offensive than using harsh words. Where the heck have you been? Pro Tip 2/3Colloquial Emphasis Add emphasis in casual conversation, not usual in formal contexts. How the heck did you do that? Pro Tip 3/3Express Frustration Can indicate a speaker's frustration without being rude or vulgar. I can't figure this out, what the heck!