名詞 cheer:

1. a cry or shout of approval
2. the quality of being cheerful and dispelling gloom
   同義詞：cheerfulness, sunniness, sunshine

動詞 cheer:

1. give encouragement to
   同義詞：hearten, recreate, embolden
2. show approval or good wishes by shouting
3. cause (somebody) to feel happier or more cheerful
   同義詞：cheer up, jolly along, jolly up
4. become cheerful
   同義詞：cheer up, chirk up
5. urge on or encourage especially by shouts
   同義詞：inspire, urge, barrack, urge on, exhort, pep up

1. They cheered loudly for their football team.
   他們大聲地為自己的足球隊喊加油。
2. He cheered up at the thought of seeing her again.
   想到再次見到她，他就高興起來。
3. He's always full of cheer in summer.
   夏天他總是高高興興的。

cheer

n.（名詞）
Lightness of spirits or mood; gaiety or joy:
高興：精神或情緒上的振奮；高興或歡樂：
例句：
a happy tune, full of cheer.
充滿了歡樂的曲調(diào)

A source of joy or happiness; comfort.
安慰：使人快樂或幸福的事；安慰

A shout of approval, encouragement, or congratulation.
喝彩：表示贊賞、鼓勵或祝賀的大喊
A short, rehearsed jingle or phrase, shouted in unison by a squad of cheerleaders.
歡呼：一小隊啦啦隊員齊聲喊的短促、反復的音韻或短語
Festive food and drink; refreshment.
酒菜：酒宴上的食品和飲料；茶點
v.（動詞）
cheered,cheer.ing,cheers
v.tr.（及物動詞）
To make happier or more cheerful:
使…更加快樂或振奮：
例句：
a warm fire that cheered us.
使我們高興的溫暖的火焰

To encourage with or as if with cheers; urge:
用歡呼聲鼓勵：用歡呼聲鼓勵…或好象用歡呼聲鼓勵…；激勵：
例句：
The fans cheered the runners on.See Synonyms at encourage
熱烈的觀眾們用歡呼聲為賽跑選手打氣參見 encourage

To salute or acclaim with cheers; applaud.See Synonyms at applaud
用歡呼聲迎接或稱贊…；鼓掌參見 applaud
v.intr.（不及物動詞）
To shout cheers.
發(fā)出歡呼聲
To become cheerful:
高興起來：
例句：
had lunch and soon cheered up.
吃完午飯后很快高興起來

來源：
Middle English chere [expression, mood]
中古英語 chere [表情，情緒]
from Old French chiere [face]
源自 古法語 chiere [臉]
from Late Latin cara
源自 后期拉丁語 cara
from Greek kara [head] * see ker-
源自 希臘語 kara [頭] *參見 ker-

【引伸】
cheer.er
n.（名詞）
cheer.ingly
adv.（副詞）