A dictionary of Confusable Phrases: More Than 10,000 Idioms and Collocations

strong arm • strong hand
strong arm —
1
. the use of superior power or physical force:
He assured the people that any attempt at lawlessness would
be put down with a strong arm. 2. (also: strong-arm man) a
person employed as a bodyguard: He was a strong arm for
bookies, collecting debts from people who had owed money
for too long.
strong hand —
1
. = strong arm 
1
: Parliament has given us the
powers to put down Fifth Column activities with a strong
hand. 2. (Cards) a card of high and commanding value: With
a very strong hand, a player may bid to Schwartz his oppo-
nents, that is, prevent them from making a single point.
strong man • strong-arm man
strong man —
1
. a man who publicly exhibits feats of great
strength: He was the product of a union between the strong
man of a traveling circus and the Chief Wardress at the
Women’s Prison. 2. a man who exercises great political power:
We got to get a strong man in the White House to kick out
the bankers and grafting politicians and racketeers.
Note: 
The expression does not correlate in meaning with the
phrase strong silent man—a man of few words who conceals
and controls his feelings: It is useless to model ourselves now
on the strong, silent man of the novel whose face is a shutter
to hide his emotions.
strong-arm man —(also: strong arm) a man employed as a
bodyguard: At one local union meeting, backed up by his
strong-arm men, he boldly declared: “I do not give a damn
whether you vote for me or not.”
stumble across something • stumble over
 something
stumble across something —find smth. by accident: Not too
long after seeing the movie, I stumbled across the collection
of short stories from which the movie got its start.
stumble over something —
1
. hit the foot against smth. and
almost fall: The pony stumbled over a stone in the path, and
unseated his rider. 2. say words awkwardly: They seemed to
have trouble starting the conversation, they stumbled over the
first words.