If a measurement is close to the correct (or standard or known or true) value, then it is said to be accurate. For example, if you use a scale to measure the weight of a 5 kg sealed bag of rice (that you bought from the market, say a reputed vendor) and the scale read 4.98 kg, then your measurement is accurate. On the other hand, if the scale reads 3.8 kg, then the measurement is inaccurate.
A related concept is that of precision or how close the measured values are to each other. For example, in the above case, if five successive measurements give you readings of 3.8 kg, then the measurement is very precise, even though it is inaccurate. Precision is independent of accuracy and your measurement can be precise but inaccurate.