1only
2alone
3-ism (in Chinese, a prefix, often combined with a suffix such as 主義|主义 or 論|论, e.g. 唯理論|唯理论, rationalism)
Examples
wéi唯yǒu有wǒ men我们yǒu有yí一gè个huā yuán花园!
唯有我们有一个花园!
If only we had a garden!
天上天下，唯我独尊。
Throughout Heaven and Earth, I alone am the honored one.
唯有加很多糖才能让我喝得下粥。
The only way I can eat porridge is with lots of sugar.