Posted in Government & Military, Internet Slang DNCO stands for Duty Non-Commissioned Officer DNCO stands for Did Not Check Out DNCO stands for Did Not Complete Operation (military shorthand) DNCO Share Pinterest Tweet Whatsapp Post navigation DNCOEAYTYK Leave a Reply Cancel replyYour email address will not be published. Required fields are marked *Comment * Name * Email * Website Save my name, email, and website in this browser for the next time I comment.