A person or official who gives authorization or official approval (British spelling of 'authorizer').
From 'authorize' plus the agent suffix '-er' (from Old English, indicating someone who performs an action). The British '-ise' spelling is standard in Commonwealth English.
In bureaucratic organizations, 'authorisers' hold real power—they're the people who can say 'yes' to things, and their role has become increasingly important as organizations grow and need more formal approval chains.
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