Oplan means: Short for operational plan, used widely in Philippine government, military, and law enforcement contexts, and carried over into Filipino-American community speech. An oplan can refer to anything from. It is military jargon and mostly appears in service contexts, war fiction, or among veterans and their families. It has drug-related associations; worth a calm conversation about which side of the topic your teen is on. This is a food-related word and harmless in itself.