συν-τηρέω, -ῶ

[in LXX: Eze.18:19 (שָׁמַר), Da TH Dan.7:28 A (נְטַר), Sir.13:12 and freq. Tob.1:11, 2Ma.12:42, al. ;]

"perfective" of τηρέω (see M, Pr. 113, 116),

to preserve, keep safe, keep close: with accusative of person(s), Mrk.6:20; with accusative of thing(s), Mat.9:17; ἐν τ. καρδίᾳ, Luk.2:19 (Arist. and later writers; cf. MM, xxiv).†

(AS)

to preserve, keep safe, keep close