As verbs the difference between established and plain

is that established is past tense of establish while plain is to lament, bewail.

As adjectives the difference between established and plain

is that established is of a religion, church etc.: formally recognized by a state as being official within that area while plain is flat, level.

As an adverb plain is

simply.

As a noun plain is

a lamentation.

Attractive is a related term of titillating.

As adjectives the difference between attractive and titillating

is that attractive is causing attraction; having the quality of attracting by inherent force while titillating is pleasantly and sensually exciting.

As a verb titillating is

.

Imbecile is a synonym of thoughtless.

As adjectives the difference between imbecile and thoughtless

is that imbecile is (dated) destitute of strength, whether of body or mind; feeble; impotent; especially, mentally weak while thoughtless is marked by or showing lack of due thought or care; careless.

As a noun imbecile

is (obsolete) a person with limited (l) (l) who can perform (l) and think only like a young child, in medical circles meaning a person who lacks the capacity to develop beyond the mental age of a normal five to seven-year-old child.

Sprint is a related term of flow.

As nouns the difference between sprint and flow

is that sprint is while flow is a movement in people or things with a particular way in large numbers or amounts.

As a verb flow is

to move as a fluid from one position to another.

Solid is a related term of arduous.

As an acronym solid

is (programming|object-oriented).

As an adjective arduous is

needing or using up much energy; testing powers of endurance.

Turbulent is a related term of extreme.

As an adjective turbulent

is violently disturbed or agitated; tempestuous, tumultuous.

As a noun extreme is

.

Vigilance is a related term of application.

As nouns the difference between vigilance and application

is that vigilance is alert watchfulness while application is the act of applying or laying on, in a literal sense; as, the application of emollients to a diseased limb.

Insist is a related term of deliver.

As verbs the difference between insist and deliver

is that insist is to hold up a claim emphatically while deliver is to set free.

Safe is a related term of first-rate.

As nouns the difference between safe and first-rate

is that safe is safe while first-rate is (military|nautical|historical) a ship of the line in the british navy that had over 100 guns on three gun decks.

As an adjective first-rate is

(military|nautical|historical) describing a ship of the line in the british navy that had over 100 guns on three gundecks.

Temerity is a related term of inconsideration.

As nouns the difference between temerity and inconsideration

is that temerity is (not countable) reckless boldness; foolish bravery while inconsideration is lack of due consideration; inattention to consequences, thoughtlessness.