Use 'lie down' to indicate resting in a horizontal position, not necessarily implying sleep.

Rest Context

'Lie down' means completely horizontal; it's different from 'sit down', which is not fully reclined.

Not Sit Down

The phrase often suggests seeking physical comfort or a break from activity.

'Lie down' metaphorically means not to resist or fight back, often in a situation of conflict or challenge.

This usage can imply weakness or lack of assertiveness and is sometimes seen negatively.

Recognize this as an idiomatic expression; the words 'lie down' are not taken literally here.