amicitia (> Eng. amity) = (friends) political allies

auctoritas (> Eng. authority) = clout, PC word for power

boni = (good men) what the senatorial old boys called each other = optimates

dignitas (> Eng. dignity) = worth, standing

dominatio (> Eng. domination) = mastery (over a slave), tyranny
        dominatio is opposed to libertas (> Eng. liberty)
The original distinction is that between a free person and a slave: if someone can dominate you, you are no better off than a slave.
If you are a free person but someone can dominate you, you suffer a loss of dignitas.

factio (> Eng. faction) = (making; taking sides) oligarchic clique

foedus (cf. Eng. federation) = (treaty, alliance) political alliance

gratia (> Eng. grace) = influence

honos (> Eng. honor) = public office

inimici (> Eng. inimical) = (un-friends) political enemies (same citizenship)
    cf. hostes (cf. Eng. hostile), who are enemies of the state (e.g. Carthaginians)

nobiles/nobilitas (> Eng. nobles, nobility) = (being known) people of senatorial families; opposed to novus homo (new man; nouveau)

optimi/optimates = (best men) what the senatorial old boys called each other

partes (> Eng. parts, parties) = sides in lawsuits, then any two opposing sides
    Sallust says people and senate formed two partes, but Cicero doesn't
    Cicero's optimates (boni)  & populares are not partes but descriptions of people who engage in politics in different ways

pauci (cf. English paucity) = the few, cf. Greek words oligarch, oligarchy
    what other people called the senatorial old boys

populares (> Eng. popular) = (of the people) nobles who worked through the popular assembly and tribunes of the people, not through the senate
    opponents called them mali (bad men), seditiosi (seditious; i.e. revolutionaries)

potentia (cf. Eng. potent) = power (bad word; cf. auctoritas)

On friendship
idem velle atque idem nolle ... firma amicitia est        to agree in everything is firm friendship
haec inter bonos amicitia, inter malos factio est         this is, among good men, friendship, among bad men, faction

On factions (usually descriptions of the nobility by their opponents):
mos partium et factionum                 the habit of [separating into] parties & factions
paucorum arbitrium                         the decision/control of a few men)
pauci nobiles                                    a few nobles
potentia paucorum                            the power of a few men
factionis potentia                            the power of a faction
paucorum potentium ius atque dicionem        the prerogative and say-so of a few  powerful men
superbia paucorum                        the arrogance of a few men
opes factionis                                wealth/resources of a faction
studia partium                                partisan zeal; lit. support of a party
ei qui rem publicam occupavere    those who have taken over the state

Powerful people have gratia, potentia, honos, divitiae ($$$)
Weak people have repulsae, pericula, iudicia, egestas (electoral defeats, dangers, lawsuits, poverty)

The danger of power or domination:
impune quae libet facere, id est regem esse    to do what one wishes, without punishment, means to be a king

The aim of all politicians:
populum (rem publicam) vindicare in libertatem    to emancipate the people [state]

Libertas, however, means "license" when used by an optimate to refer to the people.  When the old boys feel that the people have seized too much liberty, they generally declare a state of public emergency by a decree which we call the SCV (senatus consultum ultimum), the "final (most dire) decree of the senate."  (Senatus decrevit darent operam consules ne quid res publica detrimenti caperet.) Sallust describes it as follows:

"The Senate decree that the consuls should take care that the state suffer no harm. This power, through the senate, in accordance with Roman custom, is the greatest allowed to a magistracy, to prepare an army, wage war, to control in any way the allies and citizens, to have the highest command and judicial authority in civil and military affairs; otherwise without the people's command the consul has a right to none of these things."