Kill a defunct process

Many a time, when I do a "ps" or a "top", I see some processes tagged with "" meaning they are dead but they are still there :(
Killing them using -9 and process ID won't work either.

The problem is that these processes are tthose that were corrupted such that they cannot communicate (hence signalling would not work) with their parent or child process.
So, you will have to kill the parent or child process.

To find this, you can use the foll. command in linux:
$ps -ef --forest | less
Search for the word "defunct" to find the offending process and its parent. Use the parent's process ID to kill it, thereby killing the offending process also.