This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
殠 combines 歹 (death, decay) with 臭 (smell, odor). The exact historical development is uncertain, but the components suggest a meaning related to the smell of decay.
The left side 歹 suggests death or decay, and the right side 臭 means smell. Picture a decaying corpse giving off a foul odor.
For シュウ, imagine a shoe that smells so bad it reminds you of decay: shoe -> シュウ, and the stench is like the odor of death.