The word "cock-a-hoop" can be defined as being elated or boastful. Antonyms for this word would include words like humble, modest, or even ashamed. A humble person is one who is not boastful, but instead feels content and grateful for their achievements. A modest person is also similar in that they do not like to brag or show off, instead preferring to remain relatively low key. If someone is feeling ashamed, they may be experiencing feelings of guilt, regret, or even embarrassment about something they have said or done. All of these antonyms highlight the opposite of the cock-a-hoop attitude, emphasizing the importance of modesty and humility.