As an adjective mostest

is (nonstandard) most.

As an adverb mainly is

(label) forcefully, vigorously.

As nouns the difference between egomaniac and megalomaniac

is that egomaniac is a person obsessed with their own (supposed) importance while megalomaniac is one affected with or exhibiting megalomania.

In transitive terms the difference between assign and resign

is that assign is to attribute or sort something into categories while resign is to give up or hand over (something to someone); to relinquish ownership of.

As a noun assign

is an assignee.

As verbs the difference between superimposed and overlap

is that superimposed is (superimpose) while overlap is to extend over and partly cover something.

As an adjective superimposed

is positioned on or above something else, especially in layers.

As a noun overlap is

something that overlaps or is overlapped.

As verbs the difference between catalogue and contents

is that catalogue is while contents is (content).

As a noun contents is

.

As verbs the difference between demolish and crumble

is that demolish is to destroy; to destruct while crumble is to fall apart; to disintegrate.

As a noun crumble is

a dessert of British origin containing stewed fruit topped with a crumbly mixture of fat, flour, and sugar.

As nouns the difference between company and startup

is that company is a team; a group of people who work together professionally while startup is the act or process of starting a process or machine or startup can be a kind of high-low or thigh-high boot worn by rustic people.

As a verb company

is (archaic|transitive) to accompany, keep company with.

As nouns the difference between potato and irish

is that potato is a plant tuber, solanum tuberosum , eaten as a starchy vegetable, particularly in the americas and europe while irish is (as plural) the irish people.

As a proper noun irish is

the goidelic language indigenous to ireland, also known as irish gaelic.

As an adjective irish is

pertaining to or originating from ireland or the irish people.

As a proper noun craft

is .

As a noun technology is

(uncountable) the organization of knowledge for practical purposes.

As verbs the difference between surface and flow

is that surface is while flow is to move as a fluid from one position to another.

As a noun flow is

a movement in people or things with a particular way in large numbers or amounts.