A feather in your cap.

[Tdol]

You can check the definition of this English idiom here.

[svartnik]

A feather in your cap is a success that will help your future.

[RonBee]

A feather in your cap is a success that will help your future.

Yes, it's something to brag about.

~R

[IceDragon]

A feather in your cap is some occurrence or accomplishment which distinguishes you. Imagine 100 people all wearing the exact same hat ( or cap) and one person in the group has a brightly colored feather protruding from his hat. Your attention is more likely to be drawn to him/her. So, a perfect score on a test, a job well done, receipt of some high honor etc is therefore your "feather".

[easybreakable]

A feather in your cap is some occurrence or accomplishment which distinguishes you. Imagine 100 people all wearing the exact same hat ( or cap) and one person in the group has a brightly colored feather protruding from his hat. Your attention is more likely to be drawn to him/her. So, a perfect score on a test, a job well done, receipt of some high honor etc is therefore your "feather".

Amazing explanation, made it vivid, thank you!

[gulesin]

There is an idiom in Turksh as the same meaning ''partridge in the bag''':it is easy for you,the conditions are in favor of you.

[Mr.Ayed]

I think that American Indians use a white feather tied to a warior's head band as a sign of challenge for their enemies, am I right or off topic?

[Tdol]

I think that American Indians use a white feather tied to a warior's head band as a sign of challenge for their enemies, am I right or off topic?

It's found in many cultures:
A feather in your cap - Wikipedia, the free encyclopedia