수영하다 (suyeonghada) means “swim”

More examples

여름에는 수영해요.yeo reu me neun su yeong hae yo

In summer, I swim.

Arms and legs work together in water to carry the body forward.

헤엄치다heeomchida: A swimmer travels through water with repeated strokes at the surface or below it.

물에서 팔과 다리를 움직여 몸을 앞으로 나아가게 하다.mu re seo pal gwa ta ri reul um ji gyeo mo meul a peu ro na a ga ge ha da

수영 (suyeong, "swimming") combines with 하다 (hada, "to do") to form a verb meaning to swim.

In everyday polite speech, this verb uses -haeyo instead of the dictionary ending -hada.