A slang word for blundering fool, or muddle-headed person, commonly used in Singapore, especially in the army. Similar in meaning with pillock
Commander to men when outfield: Which cockanathan shat under the tree without first digging a hole to shit in? Own up or I'll make you all prone 10cm away from it for 5 minutes!
Look, that moron is late again and giving lame excuses, what a cockanathan.