noun

• (slang) The room from which a ham radio operator transmits.

noun

• (obsolete) Grain fallen to the ground and left after harvest.
• (obsolete) Nuts which have fallen to the ground.
• (obsolete) Freedom to pasturage in order to feed upon shack.
  "[…] first comes the case of tenants with a customary right to shack their sheep and cattle who have overburdened the fields with a larger number of beasts than their tenement entitles them to, or who have allowed their beasts to feed in the field out of shack time."
• (UK, US, dialect, obsolete) A shiftless fellow; a low, itinerant beggar; a vagabond; a tramp.
  "Some peple hev a fakilty two get along into the world, whilst others air poor shacks & good for nothing."

verb

• (obsolete) To shed or fall, as corn or grain at harvest.
• (obsolete) To feed in stubble, or upon waste.
  "They [turkeys] are then sold‥to the larger farmers to ‘shack’ upon the barley or oat stubbles."
• (UK, dialect) To wander as a vagabond or tramp.
• (US, intransitive) To hibernate; to go into winter quarters.

adj

• (Singapore, Singlish, slang) Alternative form of shag (“exhausted; tiring”).