Usage patterns
強固な意志a firm, unwavering will
He kept taking on challenges with a firm, unwavering will.
強固な基盤a solid foundation or base
This company has grown on a solid foundation.
強固な絆a strong, unbreakable bond
A strong, unbreakable bond formed between the two of them.
強固に反対するto firmly oppose something
The residents firmly opposed the plan.