Being a computer programmer, this word had a particular meaning for me, where a part of the programme did something other than expected.

Like unexpectedly stopping and freezing the screen.  Some very famous programs and operating systems used to have a lot of these ‘bugs’.

More familiarly for all of us, a bug is an unwanted insect pest like a fly, or an ant, though there’s a host of those pesky ‘bugs’.

You could bug someone by hanging around and asking inane questions.

You could also bug someone by surreptitiously planting a microphone on them, or somewhere in their house, car, or office.

A person could have a bug, meaning there’s some germ or bacteria they’ve picked up that makes them very ill, like a cold, or pneumonia.  Or, more than likely, it’s a bug going around.  School children are particularly susceptible.

And if you like reading books you might have caught the reading bug.

You could tell someone to bug off, that is, to go away.

I might want to bug out, as in disappear, especially if there was someone I didn’t want to see.