stealth

The cat stealthily crouched in the grass, eyeing it's intended victim and waiting for just the right moment to pounce.  

sneaky

(stealthy, stealthily)

malevolent

The malevolent spirit howled profanities through the night in the depths of the old basement.

wicked or evil

(-ly)

assuage

It took about three years for my feelings of grief to assuage after my father's death.

to make something uncomfortable feel better

(-d, -s, -ing)

dictum

There is an old dictum which states "Might makes right."

 I disagree

a short statement that expresses a general truth or principle

(dictation)

arbitrate

If your two best friends are fighting, you might arbitrate

by telling them to split it

to act between parties to resolve their differences

(-d, -ing, -s)

nauseate

The first few weeks of pregnancy were difficult for Katie because every morning she woke up feeling nauseated and dizzy

to feel sick to the point of almost vomiting.

(-d, -ing, -s, nausea nauseated)

melancholy

The one act play was so melancholy that I felt dpressed even after I left the theater

gloomy or depressed

(melancholic)

aloof

After meeting Janine for the third time, Micheal realized she wasn't shy, just aloof, because she hardly spoke and acted bored every time they went out

not friendly or forthcoming; cool and distant.

(-ly)

benign

until dill and jem excluded me from their plans, she was only another lady in the neighborhood, but a relativley benigin prescence.

Showing or expressing kindness or gentleness

(-ly)

acquiesce

We were accustomed to prompt, if not always cheerfully acquiescing to Atticus's instructions, but from the way he stood Jem was not thinking of budging.

Submit or complywithout arguing

(-ed, -ing)