extremely grateful; deeply moved with gratitude
Emphatic expression combining gratitude and deep emotion. Often used in set phrases like 感謝感激雨霰 (a flood of gratitude).
See also: 感謝感激雨あられ
I am deeply grateful for your support.
I was deeply moved with gratitude by her letter.
I am terribly grateful; thank you so much
Compound of 感謝 (gratitude) and 感激 (deep emotion). The exact origin is uncertain, but it likely arose as an emphatic expression combining the two concepts.