'something', i.e. something evil that sticks or adheres to character.

'Evil appendant', is a name for the 3 disadvantageous roots (mūla).

"There are 3 appendants: greed (lobha) is an appendant, hate (dosa) is an appendant, delusion (moha) is an appendant" (D. 33). 'Freed from appendants' (akiñcana) is a term for the perfectly Holy One (Arahat).