GET BEHIND

{v.} 1. To go too slowly: be late; do something too slowly. * /The post office got behind in delivering Christmas mail./ Syn.: FALL BEHIND. Contrast: KEEP UP. 2. {informal} To support; help. * /A club is much better if members get behind their leaders. * /We got behind Mary to be class president./ Compare: BACK OF(3). 3. {informal} To explain; find out the reason for. * /The police are questioning many people to try and get behind the bank robbery./ Syn.: GET TO THE BOTTOM OF.