حل جذري

Usually, yes, as it implies a problem is finally fixed. However, in politics, a 'radical solution' can sometimes be seen as too extreme or disruptive.

No, you don't call a person a 'radical solution'. You use it for actions, plans, or ideas.

'Nihai' means final/last. 'Jadhri' means it addresses the root. A final solution might just be the last one tried, but a root solution is the one that actually works at the base level.

You say 'Hulul Jadhriyya' (حلول جذرية). Note the feminine ending on the adjective.

The word 'Jidhr' is not in the Quran, but the concept of 'Asl' (root/origin) is used similarly.

Yes, if you are discussing something serious with a friend, like 'We need a Hal Jadhri for our travel plans!'

No. While 'radical' in English can sometimes imply political extremism, 'Hal Jadhri' in Arabic is almost always about the depth of the solution, not the violence of the method.

The opposite is 'Sathi' (سطحي) meaning superficial, or 'Shakli' (شكلي) meaning formal/superficial.

Yes, the phrase is understood everywhere because it is standard Modern Standard Arabic (MSA), though local equivalents exist.

In math, you would use 'Jidhr' for 'root', but 'Hal Jadhri' is not a standard math term; it's for real-world problems.