zweitplatziert
second-placed
Occupying second place in a competition, election, or ranking.
Der zweitplatzierte Läufer war nur wenige Sekunden langsamer als der Sieger.
The second-placed runner was only a few seconds slower than the winner.

second-placed
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second-placed
Occupying second place in a competition, election, or ranking.
Der zweitplatzierte Läufer war nur wenige Sekunden langsamer als der Sieger.
The second-placed runner was only a few seconds slower than the winner.

The word is made up of the ordinal number 'zweit' (second) and 'platziert' (placed). 'Platziert' is the past participle of the verb 'platzieren' (to place). Literally, it therefore means 'placed in second position'.
Das zweitplatzierte Team hat eine Silbermedaille gewonnen.
The second-placed team won a silver medal.
Like many participles, 'zweitplatziert' can also be used as a noun. You then say 'dem Zweitplatzierten' (the male or generic second-place finisher, dative) or 'der Zweitplatzierten' (the female second-place finisher, dative/genitive).
Der Zweitplatzierte war sichtlich enttäuscht über das Ergebnis.
The second-place finisher was visibly disappointed with the result.
This adjective is almost always used in the context of competitions. Typical areas are sports, elections, or other rankings.
Bei der Wahl wurde die Kandidatin nur knapp Zweitplatzierte.
In the election, the candidate narrowly came in second.
runner-up
'der Vizemeister' and 'zweitplatziert' both have to do with second place in a competition. 'der Vizemeister' is a noun and refers to the person or team that comes second after the winner. The word fits especially well in sports, championships, and competitions. 'zweitplatziert' is an adjective and describes someone or something in second place. It can also be used for elections or rankings. The words can be confused because both refer to second place. In practice: you say 'der Vizemeister' when naming the person or team, and 'zweitplatziert' when describing the placement.

Die zweitplatzierte Läuferin bekam bei der Siegerehrung großen Applaus.
The second-placed runner received a big round of applause at the awards ceremony.
Nach einem knappen Finale wurde unser Team Vizemeister.
After a close final, our team became runner-up.