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to be on to

to be on to

54 6.8
To know that someone has secret plans and is about to be found out
  • phrasal verb
  • Informal
translation icon : estar tras la pista de
  • The detective was on to the suspect's plan to flee the city.
  • be on to others

They notice the shifts and they notice that people are on to them.

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Examples

  • The police are on to me.

  • I thought for sure he was on to us.

  • So another team of officers, now a completely different unit, they are on to him and his activity.

  • The cops are on to Ray.

  • I think you might be on to something.

    Academic text (2013)
  • Little did Bernoulli know, he was on to something much bigger.

  • But Hegel is on to something here.

  • You've been affected, but we're on to them now, so we can keep an eye on you.

    Fiction book (1997)
  • So any reasonable person would say you're on to something big.

  • But one anomaly suggests that the researchers are on to something here.

    Blog text (27)

Synonyms

onto
vsto be on to
  • Informal
442 5.3

To become aware of a secret or plan

implies being aware specifically of others' intentions and near capture
on to something
vsto be on to
  • Informal
9 4.8

Thinking you have found an important idea or clue

focuses on finding someone's plans and nearing exposure or capture

How Aware

to know
1.0
to be on to
  • Informal
54 6.8
to suspect
925 3.6
to notice
1.0

Surface Forms

be on to infinitive
was on to past
been on to past participle
being on to present participle
is on to third person singular

Morphology

be + on + to

The meaning 'to be aware of or have discovered someone's intentions' is not directly derivable from the literal senses of 'be' + 'on' + 'to' (where 'on' is mainly locative and 'to' is a preposition). There is a weak metaphorical link (being 'on to' someone = 'on the trail of' or moving toward discovery) and the item functions like a particle-verb construction, so the relation is partially transparent but not fully predictable without exposure.

Etymology

Be on to may come from the picture of a dog following a scent, being on the trail and about to catch its prey. So, if someone 'is on to' you, they are close to finding out your secret or plan.