Drier means containing less moisture. A drier climate, drier than last year, drier wood.
Wood must be drier than about twenty per cent moisture to burn well, which is why seasoning matters. Of wine and humour, drier means less sweet and more deadpan. Note the spelling: drier is the comparative of dry, and dryer is usually the machine — though both spellings are found for both jobs and nobody is much troubled.
1adjectivedrierContaining less moisture.
“This side of the valley is much drier, and very little grows there.”
drier is a comparison of dryness.
Also accepted in games: dryer
Dry plus -er. The spelling drier for the comparative and dryer for the machine is a modern convention rather than a rule.
Middle English
driere
English, today
drier
Built from
From Middle English driere, dreyere (“one who dries”), equivalent to dry + er.
Etymology from Wiktionary, CC BY-SA