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

cover for someone • cover up for someone
cover for someone —
1
. carry out the duties of a fellow em-
ployee, absent through sickness, etc.: You’ll need to apply for
the sabbatical and train those who will cover for you while
you’re gone. 2. conceal smb.’s wrongdoing; provide an excuse
for a person: She said that Zaikas had covered for Isaac, who
was a party to the state-hospital scandal.
Note: 
The expression does not correlate in meaning with the
phrase get someone covered— provide a person with medical in-
surance: Since he has never had an injury history it was pretty
easy to get him covered.
cover up for someone — = cover for someone 2: I shall really
have to teach Neil how to lie effectively if I’m going to expect
him to cover up for me.
cover ground • cover the field
cover ground —
1
. (also: cover the ground) deal with an assign-
ment, etc. (especially efficiently or rapidly): If you want to
cover ground fast, pool your resources. 2. (of a book, etc.) treat
a subject: The book could have been greater in scope had the
author shown the ambition to cover ground rarely covered in
military history.
cover the field —(also: cover the territory) be comprehensive:
The strength of Lister’s book is that it really covers the field,
from methodology to practical examples.
cover letter • letter under cover
cover letter —(also: covering letter) a letter sent with an en-
closure to provide additional information: It’s always impor-
tant to match your qualifications to the job in the cover let-
ter.
letter under cover —(dated or formal) a letter in an envelope:
Seeing my name in the newspapers, he had sent a letter under
cover to the Admiral, expressing his desire to see me.