keen keen /ˈkiːn/

adjective

1. () Having or demonstrating ability to recognize or draw fine distinctions  ( discriminating , knifelike , penetrative , acute , incisive , keen , penetrating , piercing , sharp )
   having or demonstrating ability to recognize or draw fine distinctions
    An acute observer of politics and politicians
   an acute observer of politics and politicians
    Incisive comments
   incisive comments
    Icy knifelike reasoning
   icy knifelike reasoning
    As sharp and incisive as the stroke of a fang
   as sharp and incisive as the stroke of a fang
    Penetrating insight
   penetrating insight
    Frequent penetrative observations
   frequent penetrative observations
   
2. Having a sharp cutting edge or point  ( keen )
   having a sharp cutting edge or point
    A keen blade
   a keen blade
   
3. Painful as if caused by a sharp instrument  ( cutting , keen , knifelike , lancinate , lancinating , piercing , stabbing )
   painful as if caused by a sharp instrument
    A cutting wind
   a cutting wind
    Keen winds
   keen winds
    Knifelike cold
   knifelike cold
    Piercing knifelike pains
   piercing knifelike pains
    Piercing cold
   piercing cold
    Piercing criticism
   piercing criticism
    A stabbing pain
   a stabbing pain
    Lancinating pain
   lancinating pain
   
4. Very good  ( bang-up , corking , cracking , dandy , groovy , keen , neat , nifty , not bad , bully , great , old , peachy , slap-up , smashing , swell )
   very good
    He did a bully job
   he did a bully job
    A neat sports car
   a neat sports car
    Had a great time at the party
   had a great time at the party
    You look simply smashing
   you look simply smashing
    We had a grand old time
   we had a grand old time
   
5. Intense or sharp  ( keen , exquisite )
   intense or sharp
    Suffered exquisite pain
   suffered exquisite pain
    Felt exquisite pleasure
   felt exquisite pleasure
   

noun

1. A funeral lament sung with loud wailing  ( keen )
   a funeral lament sung with loud wailing
    The mourners sang a heartbreaking keen at the funeral.
   The mourners sang a heartbreaking keen at the funeral.
   
   

verb

1. Express grief verbally  ( keen , lament )
   express grief verbally
    We lamented the death of the child
   we lamented the death of the child