how to update avira without internet connection ?

Download Avira antivirus definition update.

you can download from here :
download avira for offline update
save to your hard drive.

open your Avira antivirus software installed.
And select in menu tab :
Update - Manual Update - and select .vdf file you download.

follow instruction from picture below.

update avira for offline / no internet connection

you can download this picture. right click on picture and select save image as.