Definition of know

Short definition: The word know means to understand something, be aware of a fact, or be familiar with a person or place. People use it when they have information, experience, or clear understanding about something.

Looking for a clear and real-life explanation of the word know? The word know is more than just having information in your head—it’s about understanding facts, recognizing people, being familiar with situations, and even feeling certain about something deep inside. In everyday English, we use know to talk about knowledge, experience, awareness, and confidence. Below, each meaning is explained in a relaxed, natural way with long examples that reflect how people truly use this word.

Verb forms: know, knows, knowing, knew, known
Related: knowledge n., knowledgeable adj., knowingly adv.
Syllable: know

1. (Verb) To have information, facts, or understanding in your mind about something.
   I know how difficult it can be to start something new, because I’ve been through the same experience before.
   She knows exactly what she wants from her career, even though the path to get there is still unclear.
   He didn’t know the answer at first, but after doing some research, everything became much clearer.

   Synonyms: understand, be aware of, have knowledge of, comprehend, grasp, realize, recognize, perceive, be informed about, be familiar with, have insight into, be conscious of
   Antonyms: not know, be unaware of, misunderstand, ignore, be ignorant of, misjudge, overlook, fail to grasp, be clueless about, misinterpret, be in the dark, have no idea

2. (Verb) To recognize or be familiar with a person, place, or situation because of experience.
   I’ve known her since we were children, so it feels natural to trust her judgment.
   He knows this city so well that he can find his way around without using a map.
   Once you know the system, everything becomes easier to manage.

   Synonyms: recognize, be acquainted with, be familiar with, have experience of, be used to, understand well, be aware of, be on good terms with, know personally, have met, be connected with, be well-versed in
   Antonyms: not recognize, be unfamiliar with, meet for the first time, be new to, have no experience of, be clueless about, fail to recognize, be a stranger to, not be acquainted with, be unaware of, be distant from, ignore

3. (Verb) To realize or feel certain about something, even without clear proof.
   I just know that everything will work out in the end, even though I can’t explain exactly why I feel that way.
   She knew something was wrong the moment she heard his voice.
   He knows deep down that he made the right decision.

   Synonyms: feel certain, be sure, sense, intuit, be convinced, trust one’s instincts, be confident about, have a strong feeling, be positive, feel in one’s bones, sense deeply, have inner certainty
   Antonyms: doubt, be unsure, question, hesitate, feel uncertain, second-guess, mistrust feelings, be skeptical, lack confidence, be unconvinced, waver, be indecisive

4. (Verb) To have learned something through study, practice, or experience.
   She knows how to speak three languages fluently, thanks to years of learning and traveling.
   He knows how to fix most technical problems, even without formal training.
   Once you know how to drive, you never really forget the skill.

   Synonyms: be skilled at, be proficient in, have mastered, be trained in, be educated in, have learned, understand how to, be capable of, be experienced in, be competent at, be practiced in, be good at
   Antonyms: not know how, be unskilled at, be inexperienced in, be incapable of, struggle with, be bad at, fail to learn, be confused about, be unfamiliar with, be incompetent at, lack skill in, be untrained in

5. (Verb) To be aware of something that has happened or is happening.
   I didn’t know about the change in schedule until this morning.
   She wants to know what’s going on before making any decisions.
   They finally knew the truth after months of uncertainty.

   Synonyms: be aware of, be informed about, learn of, find out about, hear about, discover, realize, recognize, be notified of, get to know, be conscious of, understand what’s happening
   Antonyms: be unaware of, not realize, miss information, ignore news, remain uninformed, stay in the dark, overlook details, fail to notice, not hear about, miss out on, be clueless about, not be told

6. (Figurative) To understand someone or something deeply, especially emotionally.
   She feels that he really knows her, not just her habits but also her fears and dreams.
   You don’t truly know a place until you’ve lived there for years.
   He finally knew himself after going through difficult life experiences.

   Synonyms: understand deeply, relate to, empathize with, connect with, be in tune with, grasp emotionally, truly understand, be aware of deeply, comprehend on a deeper level, see clearly, feel connected to, know inside out
   Antonyms: misunderstand, misread, fail to understand, be distant from, feel disconnected, lack empathy, misjudge character, not relate to, remain unaware, stay emotionally blind, misinterpret feelings, be out of touch