Meaning : (used colloquially) having the relationship of friends or pals.
Synonyms : matey, pally, palsy-walsy
Meaning : (used informally) associated on close terms.
Example :
A close friend.
The bartender was chummy with the regular customers.
The two were thick as thieves for months.
Synonyms : buddy-buddy, thick
Chummy meaning in Bengali (Bangla).