pain
Word family
Synonym discussion
Sense: noun/1
'Pain' is the broad everyday word for an unpleasant feeling in the body, so it can cover many kinds and levels. 'Ache' often suggests a dull, steady pain, such as a backache after carrying boxes. 'Soreness' is common after exercise, pressure, or a small injury, and usually sounds milder. 'Discomfort' is weaker than 'pain' and can mean only slight physical trouble. 'Agony' is much stronger and is used for extreme pain. So after a fall, you may feel a sharp pain in your knee; after a long hike, you may have soreness in both legs.
Etymology
English got this word through Old French from Latin. The older Latin word meant a penalty or punishment. Over time, the idea moved from punishment to the suffering that punishment or injury can cause, which is why modern English uses 'pain' for both bodily hurt and deep emotional suffering.