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

check someone up • check up on someone
check someone up —
1
. (also: give someone a check-up) give
smb. a medical examination: The doctor checked me up and
I was told I was in bad shape. 2. establish the truth about
smb.; investigate a person: The cop doesn’t even take the trou-
ble to check me up, he knows me damn well.
check up on someone — = check someone 2: The police checked
up on him, and he had an alibi. Several people testified that
they saw him at a bar in Rochester.
cheese it • say cheese
cheese it—(sl., often imper.) 
1
. stop doing smth.; leave off: I
say, cheese it! If you bang about much more you’ll have the
ceiling down. 2. run away quickly: When a police car came
into the neighborhood, we acted as if they were after us, and
the cry went out “Cheese it, the cops!”
say cheese —said to make smb. smile when taking his pho-
tograph: They are almost certainly just saying cheese to hold
their smiles…
chess player • chessman
chess player —a person who plays chess: A champion chess
player will often lose a match game to a far inferior opponent.
chessman —one of the pieces with which chess is played:
Chessmen of fanciful shapes and forms are often made as cu-
riosities.
chew the cud • chew the fat
chew the cud —think about smth. slowly and carefully: Near
the Acropolis is the Archaia Agora, ruins that were once the
square where philosophers chewed the cud.
chew the fat—(coll.) 
1
. chat at length in a relaxed manner:
Blount’s great talent is that he’s comfortable chewing the fat
with just about anybody. 2. discuss a matter, especially com-
plainingly: If anyone starts fault-finding or “chewing the fat”
he is immediately “ticked off.”
Note: 
Neither expression correlates in meaning with the phrase