Superlative form of spotty: most spotty.(adjective)
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Use "spottiest" in a sentence
"So I got in easily and I had the spottiest of all college careers."
"Less than half a century ago, America thrived with only the spottiest use of air conditioning."
"Small residential power users paid the highest rates for the spottiest service, while big customers such as factories and refineries pocketed millions in discounts and rebates."