adj

• (informal) Positioned sideways (with a side to the front).
  "There was a stack of papers in front of each seat at the table, but each stack was sideways."
• (informal) Neither moving upward nor moving downward.
  "Once we get out of this sideways economy, our figures will more accurately reflect what we're truly capable of."
• (usually with "with", informal) In conflict (with); not compatible (with).
  "He was constantly getting sideways with his boss till he got fired."

adv

• (informal) Neither upward nor downward.
  "The economy has been moving sideways for several months now."
• (chiefly US, colloquial) Not as planned; towards a worse outcome.
  "We realized the project could go sideways very quickly if we didn't get the sales and marketing people on our side."