When a boy bumps shoulders with you is he flirting?

Answer 1

Of course not. It is a possibility, but usually it is a more friendly gesture. If you have enough male friends, you would notice that they do it without trying to imply any romantic interest.

Answer 2

Not necessarily. Bumping shoulders could be accidental or just a result of being in a crowded space. Flirting typically involves more intentional and direct actions or behaviors to show romantic interest.