The letter sequence <ui> is pronounced uː in
bruise cruise fruit juice nuisance sluice suit
Actually, in nuisance the sequence is pronounced juː, as it is in suit for some speakers.
The pronunciation is ɪ in
build built biscuit circuit guild guilt
but notice that the adjective circuitous is pronounced səˈkjuːɪtəs.
There is another group of exceptional words where <ui> is pronounced wiː
The most common pronunciation of the sequence is uːɪ, as in
druid fluid ruin
Note: puissance is a term from equestrianism. Thanks to Philip Taylor for suggesting it.