除却 is a literary verb meaning 'to remove, get rid of, or eliminate' something abstract like worries, bad habits, or obstacles. In classical and formal writing, it can also function as a conjunction meaning 'except, unless' (e.g., 除却此路, 别无他法 'unless this path, there is no other way'), but that usage is not covered under the verb part of speech. This word is rarely used in everyday conversation and appears mostly in written or rhetorical contexts.