萬不得已

only when absolutely essential (idiom); as a last resort

surname Wan

ten thousand / a great number

no; not so / (bound form) not; un-

must not / may not / not to be allowed / cannot

to obtain / to get / to gain / to catch (a disease) / proper / suitable / proud / contented / to allow / to permit / ready / finished

structural particle: used after a verb (or adjective as main verb), linking it to following phrase indicating effect, degree, possibility etc

to have to / must / ought to / to need to

to act against one's will / to have no alternative but to / to have to / to have no choice / must

already / to stop / then / afterwards