Indicates being somewhat excited or agitated; used like a noun/modifier (e.g., 'a bit excited').
試合前で選手たちは少し興奮気味だった。
Before the match, the players were a bit excited.
子どもが興奮気味に新しいおもちゃの話をしていた。
The child was talking about the new toy in an excited way.
そのニュースを聞いて会場は興奮気味のざわめきに包まれた。
Hearing the news, the venue was filled with a somewhat excited murmur.