He was considered unqualified to manage the project due to his lack of formal training.

unqualified 是由前缀 un-（表示"否定"）和形容词 qualified（有资格的）组成的复合词。qualified 来自动词 qualify（使具有资格），加上 -ed 变成形容词。unqualified 字面意思是"没有资格的"，表示不具备所需的技能或资质。