A deep, long sound showing great pain or unhappiness. (Cambridge Dictionary)
A complaining noise or phrase. (Cambridge Dictionary)
If you groan, you make a long, low sound because you are in pain, or because you are upset or unhappy about something. (Collins Dictionary)
If you groan something, you say it in a low, unhappy voice. (Collins Dictionary)
If you groan about something, you complain about it. (Collins Dictionary)
Make a deep inarticulate sound conveying pain, despair, pleasure, etc. (Oxford Dictionaries)
The Spirit’s Groaning.
“Sometimes a heartfelt groan is better than a sung anthem. Tears are a language that God understands.” — Robert Smith Jr.
The Wimbledon groan – the most disheartening sound in tennis.