This entirely Tamilian term, strangely enough, has its origins in the term "off-beat" used in the British Army to refer to retired officers or soldiers.
"OB adikardhu", in Tamil, refers to the following activities: to avoid doing work, to jugaad-fy, to waste time, to chillax.
"Macha, did you study Boyle's Law?"
"Chill da. we'll OB-adchufy."
"Ey, we have seven wickets in hand. We should thulp them."
"Chanceless. No. 6 and 7 are full OB-types, da."