Usage: 3 forms in 4 verses
Form Translated As     In Verse(s)
σύμπτωμα a coincidence LXX.1Sam.6.9LXX.1Sam.20.26
συμπτώματοσ an adverse incident LXX.Ps.91.6
συμπτωμάτων adverse incidents LXX.Prov.27.9

Liddell-Scott-Jones

σύμπτωμα (sumptōma) a coincidence G:N-N

σύμπτωμα-πτωμα, ατος, τό,

(συμπίπτω) anything that happens, a chance, occurrence, τὰ σ. καὶ τὰ ἀπὸ τύχης [Refs 4th c.BC+]; ἀπὸ συμπτώματος, coupled with ἀπὸ τύχης, [Refs]; opposed to αἴτια, [σύμπτωμαπτωμα 4th-3rd c.BC: Theophrastus Philosophus “de Ventis” 17, compare 31. ">Refs 4th c.BC+]

__2 mishap, mischance, [Refs 5th c.BC+]; ἀκούσιον σ. [Refs 4th c.BC+]; ὅταν τις.. ἀδίκοις περιπέσῃ σ. [Refs 4th c.BC+]; τὰ κοινὰ κοινῶς δεῖ φέρειν σ. [Refs]
__II property, attribute, [Refs 4th c.BC+]; πνεύματος σ. [Refs 2nd c.AD+]; Νουμήνιος σ. αὐτῆς (i.e. τῆς συγκαταθετικῆς δυνάμεως) φησιν εἶναι τὸ φανταστικόν [Refs 3rd c.AD+]
__II.2 Geometry texts, property, of curve, etc., [Refs 3rd c.BC+]
__III in diseases, symptom, [Refs 1st c.BC+]; symptomata is explained by sudor nequissimus, [Refs]
__IV falling in, collapse, in Medical sense, [Refs 5th c.BC+]; of a horse, [Refs 3rd c.BC+]; σ. τῆς δυνάμεως, τῆς διανοίας, [Refs]; of the lacus Fucinus, [Refs 2nd c.AD+]