In a blockish manner; with dullness, stubbornness, or in a chunky or angular way.
Adverbial form created by adding '-ly' to 'blockish,' following standard English pattern for creating adverbs from adjectives.
You almost never see 'blockishly' used because '-ly' adverbs work better with stronger adjectives, but technically you could do something 'blockishly'—stumbling around in a chunky, uncoordinated way.
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