underpack

verb

1. To pack too little.“In spite of its subject, imminent death, Mr. Turturro said: "This was fun. I was curious to see if you could find the right tone for something like that. It was a very elusive thing, because you couldn't underpack it or overpack it. When you're doing it, you can't think about whether or not it's going to be funny, though somewhere in the back of your brain you know it could be."”
2. To pack beneath something.“A trench was dug round the front of the engine to provide the necessary working clearance and the trailing radial wheels, which had remained at ground level, were underpacked with short lengths of rail laid sideways on a sleeper foundation.”