'lenient punishment' is correct and can be used in written English.
For example, "The court gave the defendant a lenient punishment after taking into account his circumstances".
By American standards that's a shockingly lenient punishment.
A yellow card was a very lenient punishment.
The CMA will hope that at least one agency decides to cooperate early in return for a more lenient punishment.
He said those teammates were offered lenient punishment for their own doping — what he called "sweetheart deals" — in exchange for their information about him.
Thus, a person who is caught stealing might negotiate a lenient punishment by offering to pay for the item in question, often at a much higher price.
On Friday, hundreds of Sudanese in Khartoum, the capital, protested what they considered a lenient punishment and called for her to be put to death.
Judges, mirroring local public opinion, tend to give lenient punishments.
Judge Rakoff noted the crucial role of cooperators — and the lenient punishments they receive — in the American legal system.
When it comes to its own executions, however, Iran has defiantly resisted requests to introduce more lenient punishments.
Modern males ("I despair for my daughters' futures as regards to men"), the courts ("ridiculously lenient punishments") … You know what?
European football's governing body have come in for severe criticism for what have been seen as lenient punishments for offences involving racism.
