noun
(uncountable) In full primary radar: a method of detecting a distant object and determining its position, velocity, or other characteristics by analysing radio waves (usually microwaves) which are sent towards the object and which reflect off its surfaces; also, the field of study of this method.
(uncountable, by extension) Often preceded by a descriptive word: a natural (for example, in an animal such as a bat) or human-made detection method based on the analysis of reflected signals other than radio waves, as light waves or sound waves; (countable) an instance of this.
(countable, figurative) A superior ability to detect something; an awareness, an intuition.
verb
(transitive) To use a radar apparatus (noun noun, sense 1, noun, sense 1.1, or noun, sense 2) on (someone or something); to scan (someone or something) with, or as if with, radar.