By apparent, claimed, or pretended authority of the particular office or position held.
Frequently with negative connotations, suggesting that the authority is used as a pretext for illegal or corrupt behaviour, especially for an act of extortion..
Origin
Late 16th century; earliest use found in John Manwood (d. 1610), legal writer. From post-classical Latin colore officii from classical Latin colōre, ablative of color + officiī, genitive of officium, after Anglo-Norman and Law French par colur de son office under pretext of one's office.