ATM
Automated or Automatic Teller Machine

AV
Alternative Vote (or Voting)

do-or-die
de tudo ou nada

Dutchman
you'll do it, or I'm a Dutchman

either-or
an either-or situation

HBM
His (or Her) Britannic Majesty

HE
His (or Her) Excellency

HM
His (or Her) Majesty

justified
to be justified in doing this or that

knighthood
to get or receive a knighthood

LGBTQ
...queer or questioning OR

LGBTQI
...and intersex OR

LGBTQIA
...and allies OR

make-or-break
de tudo ou nada

n.p. or d.
no place or date

NEET
not in employment, education or training

o.n.o.
or near(est) offer

ob.
obiit (he or she died)

OHMS
On Her (or His) Majesty's Service

or
green or red

OR
Operating Room

partly
wholly or partly

predicate
...or bad OR

s.v.
sub verbo (under the word or term)

sooner
sooner or later

thereabouts
in Cambridge or thereabouts

turn-up
turn-ups or plain bottoms?

whenever
or whenever

whether
I don't know whether he comes or not

yuppie
...mobile professional OR