Define detecting. detecting synonyms, detecting pronunciation, detecting translation, English dictionary definition of detecting. tr.v. de·tect·ed , de·tect·ing , de·tects 1. To discover or ascertain the existence, presence, or fact of. 2. To discern : detected a note of sarcasm in the. detecting - WordReference English dictionary, questions, discussion and forums. All Free. Find 69 different ways to say DETECTING, along with antonyms, related words, and example sentences at Thesaurus.com. detecting Definitions of detecting noun a police investigation to determine the perpetrator synonyms: detection, detective work, sleuthing DETECTING definition: 1. present participle of detect 2. to notice something that is partly hidden or not clear, or to…. Learn more. singular 3rd person is detecting progressive 3rd person singular have been detecting perfect progressive Past had detected transitive verb 1 : to discover the true character of detecting drug smugglers 2 : to discover or determine the existence, presence, or fact of detect alcohol in the blood.