The term "bracing up" refers to preparing oneself mentally or physically for a challenge or difficult situation. The antonyms for the phrase would thus include words like procrastination, avoiding or shirking, neglecting, and delaying. These words describe behaviors or attitudes that indicate a lack of preparation or willingness to face difficult situations head-on. Other antonyms for "bracing up" might include words that denote a sense of defeat or resignation, such as surrendering or giving up. In contrast to these negative terms, antonyms for "bracing up" might include words like energizing, invigorating, motivating, or inspiring, which suggest a sense of readiness and enthusiasm for challenges.