The word zeal means great energy, passion, and eagerness towards a task.
Among the given options,
\[
\boxed{\text{Zeal}=\text{enthusiasm}}
\]
The other options do not match the meaning:
• Indifference means lack of interest.
• Patience means the ability to wait calmly.
• Discipline means controlled and orderly behaviour.
Hence, the correct option is \(\boxed{(B)}\).