Grammar fix
let on
reveal a secret (often used in the negative: not let on)
to allow other people to know something that is secret or private, often by accident or by not hiding it well; to admit or reveal information that you were supposed to keep hidden.
Hear it in context
Notice where the phrase sounds natural.
- She didn't let on that she already knew about the surprise party.communication
- In my opinion, it's important not to let on if you know a friend's secret, because trust is essential in any relationship.IELTS speaking
Fix the pattern
Pattern: let on (about sth) | let on (that...)
WrongDon't let on him about the party.
RightDon't let on (to him) about the party.
'Let on (to someone) ABOUT/THAT' — don't put the person straight after 'let on'.
Patternlet on (about sth) | let on (that...)
Use it right
Choose the version that sounds natural in speech.
'Let on' naturally means reveal you know something (usually in the negative). 'Gave no indication' is formal.
Build natural chunks
Words that usually travel with it.
let ondidn't let onnever let onthat she knewabout it
Don't confuse it
This sense is different from the literal meaning of 'let' (to allow) and does not mean to permit someone to do something. Instead, it is about revealing information, often unintentionally or subtly.