The phrase "had shakes" typically refers to a state of trembling or shuddering that a person experiences due to fear, anxiety, nervousness, or illness. Some antonyms of this phrase can include serene, calm, composed, tranquil, steady, and firm. These words describe a state of calmness wherein a person is in control of their body and emotions, and there is no noticeable quivering or shaking present. Other antonyms for "had shakes" can include words like confidence, poise, self-control, and composure, as they describe someone who is self-assured and confident in their actions and decisions. Overall, antonyms for "had shakes" emphasize a state of stability rather than instability or nervousness.