slack-key should also be accepted.
Except they specifically had "kīkā" in there. Other prompts don't have it, so then you could omit it.
Slack-key is a correct spelling as is slack key.
Okay, but you needed the word "guitar" included since the prompt has "kīkā."
Mahalo for the precision of your reply. If I neglected to include the word guitar, I deserve the rejection. I cannot remember my response.
What is slack key?
A beautiful, Hawaiian way of playing the 6 string guitar. Type "slack key" into your browser and have a listen ; )