What's a word for a lion that starts with g

Grown, gallant, gallore

If you mean a describing word or adjective you could try some of these:

Gainful, Gallant, Galore, Galvanized, Galvanizing, Game, Gamesome, Gargantuan, Gelastic, Gelogenic, Generative, Generous, Genial, Genteel, Gentle, Gentlemanly, Genuine, Germane, Get-at-able, Gettable, Gifted, Giggly, Giving, Glad, Glamorous, Gleaming, Gleeful, Glistening, Glorious, Glowing, Gnarly, Gnomic, Goal-oriented, Godlike, Godly, Golden, Goluptious, Good, Goodhearted, Good-feeling, Good-humoured, Good-looking, Goodly, Good-natured, Gorgeous, Graced, Graceful, Gracile, Gracious, Gradely, Graith, Graithly, Grand, Grateful, Gratified, Gratifying, Gratis, Great, Greatest*, Greathearted, Gregarious, Groovy, Grounded, Growing, Grown, Guaranteed, Gubernatorial, Guided, Guiding, Guileless, Guilt-free, Guiltless, Gutsy, Gymnastic.