make a deep inarticulate sound conveying pain, despair, pleasure, etc.

Marty groaned and pulled the blanket over his head

(of an object) make a low creaking sound when pressure or weight is applied

James slumped back into his chair, making it groan

a deep inarticulate sound conveying pain, despair, pleasure, etc.

she lay back with a groan

a low creaking sound made by an object under pressure

the protesting groan of timbers