one's best and most trusted male friend.
the most reliable, important, or respected man.
one's main boyfriend.
Words nearby main man
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for main man
noun slang, mainly US
one's best friend
a boss or leader
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012