vojnički

1. military; soldier's; army
   Deda je čuvao svoju staru vojničku uniformu. — Grandpa kept his old army uniform.
   Služio je vojnički rok u Nišu. — He did his military service in Niš.

2. in a military manner; like a soldier
   Stao je mirno i vojnički pozdravio. — He stood to attention and saluted like a soldier.
   Odgovorio je kratko, vojnički. — He answered briefly, military-style.

Vojni usually refers to the army as an institution (vojni sud), vojnički to soldiers and their manner (vojnička disciplina).