Comparative form of hearty: more hearty(adjective)
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Use "heartier" in a sentence
"If Mr. Blackwell has a heartier lunch, perhaps fish, then he tries to have just soup for dinner."
"This week Indonesian scientists met with American counterparts in Jakarta to trade ideas and seek support for projects such as plastic made from local plants, new fuel cells and heartier varieties of rice."
"It is not only healthier but it tastes heartier too."