hammer

1 hammer /ˈhæmɚ/ noun
plural hammers
1 hammer
/ˈhæmɚ/
noun
plural hammers
Britannica Dictionary definition of HAMMER
1 
[count]
a  : a tool that has a heavy metal head attached to a handle and that is used for hitting nails or breaking things apart — see picture at carpentry; see also sledgehammer
b  : a similar tool made usually of wood and used especially for hitting a surface to make a loud noise
2 
[count] : the part of a gun that strikes a charge causing the gun to shoot
3 
[count] : a piece inside a piano that strikes a string to produce a sound
4 
[count] : a stick that is shaped like a hammer and that is used to play a musical instrument
5 
a  [count] : a heavy metal ball with a flexible handle that people throw as a sport
b  the hammer : an event in which people compete by throwing a hammer
— called also the hammer throw

hammer and tongs

: in a very forceful and energetic way

under the hammer

— used to describe something that is being sold at an auction
2 hammer /ˈhæmɚ/ verb
hammers; hammered; hammering
2 hammer
/ˈhæmɚ/
verb
hammers; hammered; hammering
Britannica Dictionary definition of HAMMER
1 
a  : to force (something) into a particular place or shape by hitting it with a hammer
[+ object]
[no object]
b  [+ object] : to attach (something) with a hammer and nails
2 
informal
a  [+ object] : to hit (something or someone) in a very forceful way
b  : to hit (something) hard and repeatedly
[+ object]
[no object]
c  [no object] : to beat very quickly and forcefully
3 
[+ object] informal : to defeat (an opponent) very easily
4 
[+ object] informal : to harm or criticize (someone or something) severely — often used as (be) hammered
5 
[no object] : to keep talking about something or trying to do something — usually + at
— often + away

hammer into

[phrasal verb]
hammer (something) into (someone)
: to force (something) to be learned very well by (someone) by repeating it again and again

hammer out

[phrasal verb]
hammer out (something) or hammer (something) out
: to produce (something, such as an agreement) by a lot of discussion or argument