play by ear
to deal with a situation as it develops and without a plan
play something by ear
to play music that you have heard without having to read written music

[TahlilGaran] Dictionary of Contemporary English ▲

play by ear
play (something) by ear
1.
to deal with a situation as it develops and without a plan.
I'm not sure if I can go bowling or not, I'll just have to play it by ear.

Usage notes: sometimes used with other verbs:
I write by ear, and rarely with any exact notion of how I want it to come out.

2.
to play a piece of music after hearing it and without written music.
My brother can play anything on the piano by ear.

[TahlilGaran] English Idioms Dictionary ▲

play something by ear
play (something) by ear
1.
to deal with a situation as it develops and without a plan.
I'm not sure if I can go bowling or not, I'll just have to play it by ear.

Usage notes: sometimes used with other verbs:
I write by ear, and rarely with any exact notion of how I want it to come out.

2.
to play a piece of music after hearing it and without written music.
My brother can play anything on the piano by ear.

[TahlilGaran] English Idioms Dictionary ▲

play by ear
to play a musical instrument by remembering the tune and not by reading the music
Although the woman can't read music she can play by ear and is a very good musician.

My sister learned to play the piano by ear when she was a child.

[TahlilGaran] English Idioms Dictionary ▲

play by ear
v. phr.
1. To play a musical instrument by remembering the tune, not by reading music.
Mary does not know how to read music. She plays the piano by ear.
Joe doesn't need any music sheets when he plays his guitar; he knows many songs well and can play them by ear.
2. informal To decide what to do as you go along; to fit the situation.
■ Used with "it".
John decided to play it by ear when he went for his interview.
It was her first job and she didn't know what to expect, so we had to play it by ear.

[TahlilGaran] English Idioms Dictionary ▲