From LOTR-TCG Wiki

Hunter is a numeric Loaded Keyword that gives the Hunter character a bonus to his strength equal to the number of Hunter he has, while he is skirmishing a non-hunter character.

Gimli, Eager Hunter is skirmishing Bold Easterling. Gimli has a Strength of 6 and Hunter 3. Bold Easterling has a Strength of 8 and is a non-hunter character. In this scenario Gimli has a Strength of 9 vs Bold Easterlings 8.

Loaded Keywords
Numeric Damage + X Defender + X Ambush X Hunter X Toil X
Non-numeric Aid Archer Enduring Fierce Lurker Muster Sanctuary Ring-bearer Unhasty
Item Class [Classless] Support Area Armor Brooch Box Bracers Cloak Gauntlets Hand Weapon
Helm Mount Palantír Phial Pipe Ranged Weapon Ring Shield Staff