To infer or discover; figure. Often used with out.
To size up; study. Often used with out.
To figure out; grasp, as a result of investigation, study, or intuition.
Suss is a British slang term meaning to figure something out.
An example of suss is working out the answer to a difficult math problem.
(UK, obsolete) To arrest for suspicious behaviour.
Origin of suss
From suspect; originally suss out (“to investigate").