'fierce need' is correct and usable in written English.
It is generally used to express a powerful and urgent need for something. Example sentence: The famine had caused a fierce need for food among the villagers.
These schools were Isadora's obsession, reflecting both her determination to spread her word -- that to live was to dance -- and her fierce need to mother.
Instead, with disarming sincerity, it emphasizes his capacity for love, the gift for fellowship that, somewhat paradoxically, accompanied his fierce need for solitude.
And as in "Rashomon" the filmmaking in "Stray Dog" conveys an extraordinary sense of urgency, a fierce need to capture the complexities of human behavior while everything is still fresh and volatile.
On Roosevelt Island, students gift-wrapped some of their most cherished toys and delivered them to a local firehouse to satisfy a fierce need to connect with disaster victims.
I was gripped now – despite seriously blistered feet – with a fierce need to reach my destination, and then, as if to reward me, just as I passed the lighthouse, and the end of the promontory was in sight, the sea fret rolled back and the sun came out.
Perhaps it's a result of the cultural trend toward hyper-productivity, the fierce need to get more done in a day than anyone else.
In this hothouse of frustrated aspirations and repressed fury, the Stassos children inevitably grow up driven by fierce, unfathomed needs.
In July 1965, I heard the appeal from the government, saying that because the war was so fierce, they needed volunteers to help.
Withey is polite and soft-spoken, attributes that seem at odds with the fierce nature needed to play the low post.
In the 55th minute he was there again when Gary Kelly's fierce drive needed only the subtlest diversion to leave the Scotland goalkeeper wrong-footed.
Chattiest of those 59 could be Stuart Childerley and Kelvin Rawlings but, apart from fierce concentration needed to work the winds and tides, the winner is likely to emerge from a cleverly-campaigned club racing boat rather than a glamour grand prix contestant.
