be good form—behave according to custom or etiquette:
- It is not considered good form to arrive too early at a dinner party.
be in good form—
1. (Sport) be in good condition of health and training:
- If a horse is in good form it is likely to win a race.
2. be in good spirits:
- On Sunday she was in good form and was doing housework. She wasn’t in a huff or anything…