Inertia is a synonym of lethargy.

As nouns the difference between lethargy and inertia

is that lethargy is a condition characterized by extreme fatigue or drowsiness, or prolonged sleep patterns while inertia is the property of a body that resists any change to its uniform motion; equivalent to its mass.

Model is a related term of study.

As nouns the difference between model and study

is that model is template while study is (label) a state of mental perplexity or worried thought.

As a verb study is

(usually|academic) to revise materials already learned in order to make sure one does not forget them, usually in preparation for an examination.

Sullen is a related term of sinister.

In obsolete|lang=en terms the difference between sullen and sinister

is that sullen is (obsolete) one who is solitary, or lives alone; a hermit while sinister is (obsolete) wrong, as springing from indirection or obliquity; perverse; dishonest.

As adjectives the difference between sullen and sinister

is that sullen is having a brooding ill temper; sulky while sinister is inauspicious]], ominous, unlucky, illegitimate (as in [[w:bar sinister|bar sinister ).

As a noun sullen

is (obsolete) one who is solitary, or lives alone; a hermit.

Hard is a synonym of oppressive.

As a noun hard

is stove, heater; an enclosed space in which fuel (usually wood) is burned to provide heating, usually for cooking.

As an adjective oppressive is

burdensome or difficult to bear.

Revolter is a related term of partisan.

As nouns the difference between revolter and partisan

is that revolter is someone who revolts; a rebel or deserter while partisan is partisan (member of a body of detached light troops).

Worry is a related term of vexation.

As nouns the difference between worry and vexation

is that worry is a strong feeling of anxiety while vexation is the act of annoying, vexing, or irritating.

As a verb worry

is to seize or shake by the throat, especially of a dog or wolf.

As nouns the difference between area and reach

is that area is a measure of the extent of a surface; it is measured in square units while reach is the act of stretching or extending; extension; power of reaching or touching with the person, or a limb, or something held or thrown.

As a verb reach is

to extend; to stretch; to thrust out; to put forth, as a limb, a member, something held, or the like.

As an acronym REACH is

Registration, Evaluation and Authorisation of Chemicals

Raid is a related term of rifle.

As an acronym raid

is (computing) a redundant array of inexpensive disks, or, less frequently restated as a redundant array of independent disks.

As a verb rifle is

.

Awful is a related term of lurid.

As adjectives the difference between awful and lurid

is that awful is oppressing with fear or horror; appalling, terrible while lurid is shocking, horrifying.

As an adverb awful

is (colloquial) very, extremely; as, an awful big house.

Commotion is a related term of jumble.

As nouns the difference between commotion and jumble

is that commotion is a state of turbulent motion while jumble is a mixture of unrelated things.

As a verb jumble is

to mix or confuse.