dunno
v. A2 Elementary US //dəˈnoʊ// UK //dˈʌnəʊ// dun·no
v. a casual way to say 'I do not know'. You use this in spoken English when you want to sound relaxed.
v. a phonetic reduction of 'I do not know', used primarily in informal speech and writing.
I dunno, maybe we should go later.
When asked about the meeting time, she shrugged and said she dunno.
The interviewee's hesitant 'dunno' revealed a lack of preparation that formal language might have concealed.
Written form of an informal pronunciation of don't know that is a reduction of do not know or does not know.
Usage
Functions as a single-word substitute for the clause 'I do not know'.
Pitfall
I dunno notI dunnoDunno already includes the negation 'not'; adding another 'not' creates a double negative.