Wiktionary
hail fellow well met
alt. A sociable, friendly, usually male person. n. A sociable, friendly, usually male person.
Wikipedia
Hail fellow well met
"Hail fellow well met" is a somewhat archaic English idiom used when referring to a person whose behavior is hearty, friendly, and congenial.
Usage examples of "hail fellow well met".
He would smile, laugh, be hail fellow well met until you learned to look into his eyes.
All his life he had been a jolly hail fellow well met: he had put on a rather becoming paunch, his cheeks were well filled out and red as a beet, his manners were easy and indolent, and he seemed destined to live on into a ripe old age, sound and healthy as a nut.