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motionlessly (e.g. stand, wait); (be) still
fixedly (e.g. gaze, stare); intently (e.g. listen, think)
patiently (endure); stoically
firmly (e.g. hold); restrained
猫がじっと窓の外を見ていた。
The cat was staring out the window motionlessly.
じっと我慢して待つしかない。
We have no choice but to wait patiently.
彼はじっと目を閉じて考えていた。
He was thinking with his eyes closed motionlessly.