AWS Lambda
Developer Guide

Step 5: Delete the Lambda Function and IAM Role (AWS CLI)

Execute the following delete-function command to delete the helloworld function.

$ aws lambda delete-function \ --function-name helloworld \ --region us-west-2 \ --profile adminuser

Delete the IAM Role

After you delete the Lambda function you can also delete the IAM role you created in the IAM console. For information about deleting a role, see Deleting Roles or Instance Profiles in the IAM User Guide.