Experimental

google

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late 15th century (in the sense ‘having personal experience’, also ‘experienced, observed’): from medieval Latin experimentalis, from Latin experimentum (see experiment).

wiktionary

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experiment +‎  -al [1]

etymonline

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experimental (adj.)

mid 15c., "having experience," from experiment (n.) + -al (1). Meaning "based on experiment" is from 1560s. Meaning "for the sake of experiment" is from 1792.