1. Vocabulary
From The Guide to The ABC Of Plain Words by Sir Ernest Gowers

This group can be divided into three:

1. Words and phrases liable to be used superfluously, unsuitably, or wrongly. Here is a list of words of this sort that you will find in the A.B.C.:

Achieve
Adumbrate
Advert
Advise
Aggravate
Alibi
Alternative
And/or
Angle
Anticipate
Appreciate
Apprise
Approximately
A priori
Apt
As and As From
As and when
As to
Aspect
Assist
Availability
Background
Backlog
Basis
Beg (to)
Beg (Question)
Bilateral
Bottleneck
Brackets
Breakdown
Calculated
Case
Ceiling
Character
Claim
Collusion
Commence
Comparatively
Concerned
Confirm
Connexion
Considerable
Consideration
Contact (v.)
Course
Deadline
Dearth
Decimate
Deem
Definite(ly)
Desire
Develop
Dilemma
Distant
Donate
End
Entail
Envisage
Essential
Evacuate
Event
Eventuate
Evince
Experience
Fact
Far
Favour
Feasible
Feature
Following
Former
Fraction
Function (v.)
Furthermore
Global
Got
Group
Hand (to)
Help
Hereto
Idem
If, If & when
Implement
Inasmuch
Incidentally
Inclined
Inculcate
Individual
Infers
Inform
Information
Instance
Inst.
Involve
Item
Lack
Latter
Leading question
Liable
Likely
Limited
Liquidate
Literally
Loan
Locate,Location
Major
Majority
Materialise
Means
Meticulous
Multilateral
Mutual
Occasion
Optimistic
Optimum
Otherwise
Overall
Particular
Per
Percentage
Peruse
Phenomenal
Please find
Point of view
Position (n.)
Position (v.)
Position
Prepared to
Prior to
Prohibit
Prone
Proportion
Proposition
Protagonist
Provided that
Prox.
Purport (n.)
Purport (v.)
Question
Re
Reaction
Realistic
Recrudescence
Redundant
Relatively
Rendition
Require
Respective(ly)
Sabotage
Same
Service (v.)
Short supply
Special pleading
Specific
Stage
Standpoint
Steps (take)
Sterilise
Substitute
Such
Such Time As
Sufficient
Target
Thereto/with
Transmit
Transpire
Ult.
Unduly
Unilateral
Until
Utilise
Very
Viewpoint
While
Worth (while)

2. Pairs of words liable to be confused. Each of the following pairs will be found in the A.B.C. under the first word of the pair.

Adherence/Adhesion
Affect/Effect
Alternate/Alternative
Autarchy/Autarky
Averse/Adverse
Compare to/with
Comprise/Compose
Consequent/Consequential
Consist in/of
Continual/Continuous
Defective/Deficient
Definitive/Definite
Dependant/Dependent
Deprecate/Depreciate
Desiderate/Desideratum
Direct/Directly
Disassociate/Dissociate
Disinterested/Uninterested
Disposal/Disposition
e.g./i.e.
Enquiry/Inquiry
Factitious/Fictitious
Forego/Forgo
Hard/Hardly
Imply/Infer
Less/Fewer
Meantime/Meanwhile
Practical/Practicable
Resort, Resource,Recourse
Verbal/Oral
Waste/Wastage

Changes in the meaning of words

De/Dis (use of as prefixes, e.g., decontaminate)

New Verbs

Non (use of as prefix)