chum up
B2 informal intransitive
In simple words
To make friends with someone and start being close with them
Literal meaning: 'Chum' is an informal word for a close friend; 'up' suggests the formation or building of that friendship
Meanings
1 B2
idiomatic
informal
To become friends with someone, especially quickly or in a new environment
"She chummed up with a group of other exchange students during orientation week."
Usage notes
British English. Often used with 'with': 'chum up with someone'. Slightly dated — more common in older British English — but still understood and used. Suggests actively becoming friends rather than a pre-existing friendship. More neutral than 'cosy up to' (which implies ulterior motives).
Commonly used with
with quickly immediately strangers classmates neighbour
Forms
Base
chum up
I/you/we/they
3rd person
chums up
he/she/it
Past simple
chumed up
yesterday
Past participle
chumed up
have + pp
-ing form
chuming up
continuous
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