"Instant" is defined as occurring immediately, so "immediately" is the best answer choice! "Delayed" means taking more time to happen than was originally predicted, making it a loose antonym, or opposite, of "instant," and the other answer choices are not related in meaning to "instant."

"Ancient" means very old.

"Daily" means occurring everyday. Shallow means not deep. Dirty means not clean. Selfish describes someone who cares only about himself. Skinny describes someone who is thin.

"Idle" means inactive, so "inactive" is the correct answer. To help you, "cheerful" means happy, "generous" means giving, and "disrespectful" means rude.

"Always" and "forever" have a similar meaning.

"Seldom" is an adjective that means rare, so "rare" is the correct answer.

"Sudden" is defined as occurring quickly and unexpectedly; thus, "unexpected" is the best answer choice.

"Coincidental" means occuring by chance, and you might call a "coincidental" meeting a "chance" meeting. So, "chance" is the correct answer. None of the other answer choices are close in meaning to "coincidental": "reluctant" means not eager and resistant; "concerned" means worried or troubled; to "observe" something means to watch it; and "suggest" means share an idea about what to do or how to do something.

"Swift" means fast or quick.

The words "stealthy" and "swift" are synonymous. They both refer to something that is quick. The words "slow" and "sluggish" mean the same thing; they refer to something that is not fast. "Loud" and "booming" are synonymous; they refer to something very loud. Identifying this relationship between the answer choices will help you arrive at the correct answer.