intransitive verb
Definition: To make a low sound that shows discomfort, pain, or annoyance.
Example: He let out a groan when he realized he had forgotten his keys.
noun
Definition: A low sound made to express pain, discomfort, or displeasure.
Example: She let out a groan when she realized she had forgotten her keys.
transitive verb
Definition: To make a low sound of pain or discomfort, often expressing unhappiness or annoyance.
Example: He began to groan when he realized he had forgotten his homework.