supposed to

2.1

To be expected to happen or to be required to do something

phrasal verb
/səˈpoʊzd tu/

: se supone que

The train is supposed to arrive at 8:15, but it's running late.

Examples

Isn't he supposed to be here?
You are supposed to turn off your phone during the movie.
I wasn't supposed to open the gift until my birthday.
You're supposed to call her.
The meeting is supposed to start at 10 AM, so please be on time.
Students are supposed to complete their assignments by Friday.
You are supposed to wear a helmet while riding a bike.

Synonyms

to expect

vssupposed to

∞ 2.0

To think someone should do something because it is usual or needed

is less forceful, expressing general expectation or intention

meant to be

vssupposed to

246 3.7

Planned or seen as certain to happen

is used more for practical expectation or required action

obligated

vssupposed to

20 4.2

Required by law or duty to do something

can be less formal, showing ordinary expectation or intent

supposed

vssupposed to

3.7

Expected to do something by rules or plans

is broader, covering general expectation and personal intention

expected

vssupposed to

1.2

Likely to happen or be true

adds a requirement or duty sense beyond mere likelihood

should

vssupposed to

1.0

To say that something is likely to happen or be true

adds an obligation or instruction sense beyond likelihood

ought

vssupposed to

3.4

To be expected or right to do something and likely to happen

focuses more on neutral expectation or practical intention

Antonyms

optional

99 3.3

Not required, so you can choose whether to have or use it

prohibited

Formal

1 3.7

Not allowed by law or by an authority

How Expected

to must

1.0

required

Formal

1.4

meant to be

246 3.7

supposed to

2.1

expected

1.2

Surface Forms

supposed to infinitive

supposed to past

supposed to past participle

supposed to present participle

supposed to third person singular

Morphology

supposed + to

The meaning 'expected/obliged to' is directly derivable from combining 'supposed' (expected/obliged) with the infinitival marker 'to' which links the adjective to the action; a B1 learner who knows both constituents can readily infer the meaning. Although 'to' is a grammatical marker and the construction is somewhat grammaticalized, the semantic composition is straightforward and cross-linguistically common, so it is transparent.

Etymology

Supposed to comes from the verb suppose, which once simply meant 'to think' or 'expect'. Imagine people saying something is supposed to happen because they think it should. So the phrase now means 'expected' or 'required'.