All the words are taken from Cambridge IELTS readings. Meanings and examples are taken from Cambridge online dictionary.

• disaster

(an event that results in) great harm, damage, or death, or serious difficulty:

An inquiry was ordered into the recent rail disaster (= a serious train accident).
It would be a disaster for me if I lost my job.
This is one of the worst natural disasters ever to befall the area.
Heavy and prolonged rain can spell disaster for many plants.
Everything was going smoothly until suddenly disaster struck.
Inviting James and Ivan to dinner on the same evening was a recipe for disaster (= caused a very difficult situation) – they always argue with each other.

to be very unsuccessful or extremely bad:

The evening was a complete disaster.
As an engineer, he was a disaster.

More examples

The destruction of the rain forests is an ecological disaster.
The plane narrowly avoided disaster when one of the engines cut out on take-off.
Let us pray for the victims of this terrible disaster.
News of the disaster shocked the whole world.
Floods and earthquakes are natural disasters.

• convenient

suitable for your purposes and needs and causing the least difficulty:

Our local shop has very convenient opening hours.
A bike’s a very convenient way of getting around.
[ + that ] It’s very convenient that you live near the office.
[ + to infinitive ] I find it convenient to be able to do my banking online.
What time would it be convenient for me to come over?

near or easy to get to or use:

a very convenient bus service
Our new house is very convenient for (= near to) the kids’ school.

More examples

It’s very convenient for me to get to the station.
It’s not really convenient for you to come this afternoon.
The house is in a convenient location for travelling to London.
It would be more convenient if I could pick up the children at four.
I find ready cooked meals very convenient.

• stumble

to step awkwardly while walking or running and fall or begin to fall:

Running along the beach, she stumbled on a log and fell on the sand.
In the final straight Meyers stumbled, and although he didn’t fall it was enough to lose him first place.

fall = She slipped and fell.
drop = Several apples dropped from the tree.
collapse = Several buildings collapsed in the earthquake.
crumple = He fainted and crumpled into a heap on the floor.
tumble = A huge rock tumbled down the mountain.
plunge = Four of the mountaineers plunged to their deaths when their ropes broke.