【Impassioned】 , 【passionate】 ,  【ardent】 ,  【fervent】 ,  【fervid】 ,  【perfervid】  mean actuated by or showing intense feeling.

【Impassioned】 , though applicable to persons, is more often found in reference to utterance or artistic expression or to the mood or mental state which evokes such utterance or expression. The word usually implies intensity without violence and feeling of such depth, sincerity, and potency that it passes naturally and inevitably from the person into his expression.

【Passionate】 , on the other hand, implies vehemence and, often, violence of emotion; when the latter idea is suggested, the word also may connote loss of rational guidance or wasteful diffusion or misdirection of emotional power.

【Ardent】  differs from  【passionate】 largely in its freedom from derogatory implications and in its connotations of qualities suggestive of flame or fire. It is especially appropriate when vehemence is implied and the intense feeling expresses itself in eagerness, zeal, enthusiasm, or acts of devotion.

【Fervent】 also implies a quality of fire, but it suggests a fire that glows rather than one that bursts into flame. Hence, though it implies strength and depth of feeling, it more often suggests steadiness than vehemence and inward quiet rather than outward activity. It is applicable especially to wishes, prayers, or hopes that are heartfelt or devout, but it is also applied to an emotion, or to a person feeling such an emotion, that is free from turbulence.

【Fervid】 , like  【impassioned】 ; is applied more to moods and expressions than to persons; in contrast to  【impassioned】 , however, it sometimes suggests more obvious, more warmly expressed, and, often, more spontaneous emotion.

Frequently it carries a strong suggestion of feverishness which distinguishes it sharply from  【fervent】 ; thus,  【fervent】  thanks suggest the depth and sincerity of the emotion which prompts them;  【fervid】 thanks suggest profuseness or an overwrought state of mind.

【Perfervid】  carries an implication of too great emotional excitement or of overwrought feelings; more than  【fervid】 , it casts doubt upon the sincerity of the emotion that is displayed with vehemence.