Synonyms for dude

Most common

1. Fella — A man, generally a younger man

man, homie, fellow, geezer, dog, dummy, fella slang, bro slang, chap slang dated UK, bruh slang, bloke slang UK AU, hoss slang US, punk slang dated, cat dated, gate dated, cove dated UK, cuh slang, broseph slang, broha slang

2. Fop — A man who is very concerned about his dress and appearance; a dandy, a fop

3. Buddy — A term of address for someone, often but not exclusively a man, particularly when hailing, cautioning them or…

Other

drugstore cowboy, sport, buster slang informal

n. 1
A man, generally a younger man.
So we were at the mall and these two dudes just walk up to us and say "hi".
n. 2
A term of address for someone, often but not exclusively a man, particularly when hailing, cautioning them or offering advice.
Hey, dude, how's it going?
n. 3
A man who is very concerned about his dress and appearance; a dandy, a fop.

Use in printed books, per decade from 1850 to 2019.

3 letters: man¹, dog¹, cat¹, bro¹, fop¹, cuh
4 letters: gate¹, mate¹, punk¹, buck¹, chap¹, cove¹, beau¹, bruh, hoss¹
5 letters: blood¹, sport¹, buddy², blade¹, spark¹, dummy², swell¹, fella², bloke¹, homie, dandy², sheik¹, broha
6 letters: fellow², sheikh¹, buster², geezer, masher
7 letters: gallant², broseph, coxcomb, fribble
8 letters: macaroni⁴, popinjay
9 letters: exquisite³
11 letters: metrosexual⁵

The small number after each word is its number of syllables (buddy² = 2 syllables).