What does 'onto him' mean?

[Tan Elaine]

The salesman was trying to deceive me, but I was onto him.
What does 'onto him' mean? Thanks.

 

[probus]

It means you have successfully guessed his secret intentions.

 

[BobK]

:up: As in 'onto his trail' or 'onto his game' or 'onto his tricks'. Whatever he said, because you knew 'where he was coming from', you could guess what he REALLY wanted.

b

 

[emsr2d2]

A spy who realises that someone has discovered his true identity or true purpose might contact his handler and say "Pull me out. I think they're onto me".

 

[5jj]

I still prefer 'on to' as two separate words.

 

[emsr2d2]

I still prefer 'on to' as two separate words.

I toyed with that while I was typing it and genuinely couldn't decide between "on to me" and "onto me" so I stuck with the format from the rest of the thread.

 

[BobK]

In most TV crime dramas they avoid the problem by saying 'I think they made me'.

b

 

[Rover_KE]

I still prefer 'on to' as two separate words.

Some would consider only onto to be correct in this case.

I was taught the difference as follows:

'We walked onto the beach.' (We left the roadway and stepped on the sandy shore.)

'We walked on to the beach.' (After stopping for a rest we carried on until we reached the sandy shore.)

Rover