Poetic and somewhat old-fashioned; describes a burning, impatient desire or enthusiasm. Often used in literary or elevated contexts.
He harbored an ardent feeling in his heart.
An eager spirit drove her forward.
impetuously; eagerly; ardently
fervent spirit; intense enthusiasm; burning passion
The exact derivation is uncertain. The kanji 弥 (increasingly) and 猛 (fierce) are likely ateji chosen for their meanings, but the word itself may be of native origin.