Quick Definition
I cause to appear
Strong's Definition
to make apparent, i.e. (passively) to appear (neuter participle as noun, a spectacle)
Derivation: from a derivative of G5316 (φαίνω);
KJV Usage: sight
Thayer's Greek Lexicon
φαντάζω: (φαίνω); present passive participle φανταζόμενος; from Aeschylus and Herodotus down; to cause to appear, make visible, expose to view, show: τό φανταζόμενον, the appearance, sight, Heb_12:21.
Mounce Concise Greek Dictionary
φαντάζω phantazō 1x
to render visible, cause to appear; pass. to appear, be seen;
τὸ φανταζόμενον , the sight, spectacle, Heb_12:21
Abbott-Smith Greek Lexicon
** φαντάζω ( < φαίνω ),
[in LXX : Wis_6:16 , Sir_31:5 (34:5) * ;]
to make visible. In cl . used in pass . only, = φαίνομαι , to become visible, appear: ptcp ., Heb_12:21 .†
Moulton & Milligan — Vocabulary of the Greek NT
φαντάζω [page 664]
In its only occurrence in the NT (Heb. 12:21) the pass, participle of this verb is used, as in classical Greek, = appearing : cf. the magic P Lond 121 .888 (iii/A.D.) (= I. p. 112) φανταζομένη ἀγρυπνοῦσα , in an address to the moon-goddess. For the sense make visible, see P Oxy XVI. 1873 .2 (late v/A.D.), a letter in highflown language describing a riot at Lycopolis ἔ ]τ̣ι τὴν Λυκοπολιτῶν στάσιν καὶ μ̣[α ]νίαν ϕ̣[αντά ]ζ̣ο̣μαι , I still see in imagination the riots and madness at Lycopolis (Edd.). Cf. also M. Anton, x. 28 φαντάζου πάντα τὸν ἐφ᾽ ᾡτινιοῦν λυπούμενον , picture to thyself every one that is grieved at any occurrence whatever (Haines).
STEPBible — Tyndale Abridged Greek Lexicon
φαντάζω
(φαίνω) [in LXX: Wis.6:16, Sir.31:5 (34:5)* ;]
to make visible. In cl. used in pass. only, = φαίνομαι, to become visible, appear: ptcp., Heb.12:21.†
(AS)