一、用作动词时的区别

两者用作动词都可表示“打败”、“战胜”、“击败”等，常可互换，只是 defeat 比 beat 更正式，其后的宾语通常是比赛或战斗的对手。如：

They beat [defeated] the enemy. 他们打败了敌人。

He beat [defeated] me at swimming. 他游泳胜过了我。

We beat [defeated] their team by ten points. 我们以10分的优势胜了他们队。

比较：win 表示“赢”，与“打败”同义，但其后所接宾语不同。win 通常接表示比赛或战斗方面的名词作宾语。如：

正：He beat [defeated] me at chess. 他下棋赢了我。

正：He won the game (the race). 他赢了比赛。

误：He won me at chess. / He beat [defeated] the game.

二、用作名词时的区别

两者也可用作名词，但含义不同：

(1) 名词 beat 通常表示“打击(声)”。如：

We heard the beat of a drum. 我们听到了打鼓的声音。

Can you hear the beat of my heart? 你能听到我心脏跳动的声音吗?

(2) 名词 defeat 通常表示“失败”、“战胜”等( 视含义的具体与抽象，可用作可数或不可数名词)。如：

Our basketball team suffered another defeat. 我们的篮球队再次败北。

What he said meant admitting defeat. 他说的话就意味着承认失败。

【Conquer】 , 【defeat】 , 【vanquish】 , 【overcome】 , 【surmount】 , 【subdue】 ,  【subjugate】 , 【reduce】 , 【overthrow】 , 【rout】 , 【beat】 , 【lick】 all mean to get the better of or to bring into subjection whether by the exercise of force or of strategy.

【Conquer】 and 【defeat】  are perhaps the most general.

【Defeat】 usually signifies merely the fact of getting the better of or winning against and may imply no more than a temporary checking or frustrating.

【Conquer】 , however, usually implies a large and significant action (as of a large force in war) or an action involving an all-inclusive effort and a more or less permanent result.

【Vanquish】 suggests a significant action of a certain dignity usually in the 【defeat】 of a person rather than a thing and usually carrying the suggestion of complete 【defeat】 .

【Overcome】  usually implies an opposing, more or less fixed obstacle to be dealt with and a high degree of effectiveness in dealing therewith whether by direct conflict or perhaps more often by indirect means (as evasion or substitution).

【Surmount】 , like 【overcome】 , implies an opposing, more or less fixed obstacle but carries the idea of surpassing or exceeding rather than overcoming in face-to-face conflict.

【Subdue】 ,  【subjugate】 , and 【reduce】 all throw emphasis upon the condition of subjection resulting from 【defeat】 .

【Subdue】 signifies to bring under control by or as if by overpowering.

【Subjugate】  signifies to bring into and keep in subjection, often as a slave is in subjection.

【Reduce】 signifies surrender and submission but usually of a town or fortress under attack or siege.

【Overthrow】 is much like  【overcome】 but carries the strong idea of disaster to the overthrown.

【Rout】 always suggests a 【defeat】 so complete as to cause flight or the complete dispersion of the opposition.

【Beat】 and 【lick】 are characteristic of a less formal style of expression or level of usage than the preceding verbs.

Both come close to 【defeat】 in meaning but distinctively 【beat】 (see also 【BEAT】 1) is rather neutral in this sense, except that occasionally it may imply the finality though not the scope of 【vanquish】 while  【lick】 usually implies a complete humbling or reduction to impotency and ineffectiveness of the one defeated.