The Hebrew adjective ashem means 'guilty' — the objective legal and moral status of guilt before God, not merely a subjective feeling. It is closely related to the noun asham (H817, 'guilt offering') and the verb asham (H816).
The asham (guilt offering) system in Leviticus was Israel's divinely prescribed mechanism for addressing trespass and breach of trust. The one who was ashem — objectively guilty — was required to bring restitution plus a sacrifice.
Isaiah 53:10 uses the cognate noun in its climactic declaration: 'the LORD makes his life a guilt offering (asham).' The Servant bears Israel's guilt — substitutionary atonement, foreshadowed in Levitical law and fulfilled in Christ.