Definition of susses:
(v) :
(transitive, UK, Australia, New Zealand, often with "out") To discover, infer or figure out.
(v) :
(transitive, UK, Australia, New Zealand) To study or size up, to check out (examine).
(adj) :
(UK, Australia, New Zealand, US, colloquial) Suspicious; suspect.
(n) :
(UK) Suspicious behaviour; the act of loitering with intent.
(n) :
(UK) Social nous.
(v) :
(transitive, UK, obsolete) To arrest for suspicious behaviour.