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high tension (as in electronics, etc.); high-tensile (e.g. steel)
excited; enthusiastic; hyped; high-strung; worked-up; intense
彼女はいつもハイテンションだ。
She's always high energy.
朝からハイテンションで疲れる。
Being high energy from morning is tiring.
ハイテンションな人が苦手だ。
I'm not good with high-energy people.