This is the 14207th most frequent Korean word.
명함을
"명함을" means "business card" (in the accusative form).
In this sentence, '명함을' refers to the object of the action '건네주다' (to hand over), specifying a business card being given.
그는 명함을 건네주며 자신을 소개했다.
He handed over his business card and introduced himself.
Here, '명함을' acts as the object of '받다' (to receive), emphasizing the significance of obtaining a business card.
명함을 받는 것이 중요한 첫인상이다.
Receiving a business card is an important first impression.
In this case, '명함을' specifies the object being printed, '인쇄하다' referencing the production of business cards.