I'd go with ruthless.
In Macbeth, the word "mettle" is used to describe one's character, courage, or resilience. For example, Lady Macbeth refers to her husband's mettle when discussing whether he is fit to be king.
Macbeth and Lady Macbeth plan to blame the murder of King Duncan on his chamberlains by framing them with the daggers used in the assassination.
We never really see any evident signs of flattery in the play Macbeth.
The adjective "open" could be used to describe a mouth that is not closed.
That's the technique Lady Macbeth used to enlist Macbeth in the plot to kill Duncan.
Both Macbeth and Lady Macbeth worry about it. She says, "Why did you bring the daggers from the place?" when Macbeth fails to leave them there. She wants them left to incriminate the guards. But Macbeth worries that they may not incriminate the guards enough, so he kills them.
An adjective would be used to describe a noun.
The adjective "rippling" can be used to describe waves.
"Beautiful" is a common adjective used to describe lilies.
'Friendly' is an adjective because you'd use it to describe someone. Any word that can be used to describe someone (a noun) is an adjective.
Wet can be used as an adjective. It can also be used as a verb to describe an action.
adjective