As nouns the difference between contributions and roles

is that contributions is while roles is .

As adjectives the difference between ketogenic and ketonic

is that ketogenic is (biochemistry) relating to ketogenesis while ketonic is (organic chemistry) of, relating to, or being a ketone.

As a noun pathos

is pathos.

As an adjective sentimental is

characterized by sentiment, sentimentality or excess emotion.

As adjectives the difference between obscure and infamous

is that obscure is dark, faint or indistinct while infamous is having a bad reputation, disreputable; of bad report; notoriously vile; detestable; widely known, especially for something bad.

As a verb obscure

is (label) to render obscure; to darken; to make dim; to keep in the dark; to hide; to make less visible, intelligible, legible, glorious, beautiful, or illustrious.

As adjectives the difference between arbitrary and conscious

is that arbitrary is (usually|of a decision) based on individual discretion or judgment; not based on any objective distinction, perhaps even made at random while conscious is alert, awake.

As a noun arbitrary

is anything arbitrary, such as an arithmetical value or a fee.