undercast

noun

1. (countable, uncountable)An unbroken or nearly unbroken cloud layer below the point of observation.

   “Undercast is common on Mount Washington.”

2. (countable, uncountable)An air-passage crossing a road in a mine by means of an airtight box or channel beneath it.

verb

1. To allocate the parts in (a play or film) to insufficiently skilled actors.
2. To throw under or beneath.