As adjectives the difference between fortuitous and abrupt
is that fortuitous
is happening by chance; coincidental or accidental while abrupt
is (obsolete|rare) broken away (from restraint) .
As a verb abrupt is
(archaic) to tear off or asunder
As a noun abrupt is (poetic) something which is ; an abyss
Happening by chance; coincidental or accidental.
Happening by a lucky chance; lucky or fortunate.
(legal) Happening independently of human will.
(obsolete, rare) Broken away (from restraint).
Without notice to prepare the mind for the event; sudden; hasty; unceremonious.
* (rfdate) (William Shakespeare), Henry VI Part I, II-iii
- The party came to an abrupt end when the parents of our host arrived.
Curt in manner; brusque; rude; uncivil; impolite.
- The cause of your abrupt departure.
Having sudden transitions from one subject or state to another; unconnected; disjointed. [ ]
* (rfdate) (Ben Jonson)
(obsolete) Broken off.
- The abrupt style, which hath many breaches.
Extremely steep or craggy as if broken up; precipitous. [ ]
* (rfdate) (Thomson)
(botany) Suddenly terminating, as if cut off; truncate.
- Tumbling through ricks abrupt .
* (precipitous) broken, rough, rugged
* (without time to prepare) brusque, sudden
* (uncivil)blunt, brusque
* (without transition) disconnected, unexpected
(archaic) To tear off or asunder.
* (rfdate) Sir T. (Browne)
To interrupt suddenly.
- Till death abrupts them.
(poetic) Something which is ; an abyss.
* (rfdate) (Milton)
- Over the vast abrupt .