Lexical Definition

‎πληροφορέω‎ plērophoréō (play-rof-or-eh'-o) to fulfill G:V
from ‎πλήρης‎ and ‎φορέω‎

most surely believe, fully know (persuade), make full proof of.

Usage: 7 forms in 7 verses
Form Translated As     In Verse(s)
πληροφόρησον do fully carry out 2Tim.4.5
πληροφορηθῇ may be fully accomplished 2Tim.4.17
πληροφορηθεὶσ having been fully assured Rom.4.21
πληροφορείσθω should be fully assured Rom.14.5
πεπληροφορημένων accomplished Luke.1.1
πεπληροφορημένοι fully complete Col.4.12
επληροφορήθη have full assurance LXX.Eccl.8.11

Abbott-Smith

πληροφορέω, -ῶ, [in LXX: Ec 8:11 (מָלֵא)*;]
1. to bring in full measure, hence, to fulfil, accomplish: Lk 1:1, II Ti 4:5, 17.
2. to persuade, assure or satisfy fully (so in π.; v. Deiss., LAE, 82 f.; M, Th., 9): pass., Ro 4:21 14:5, Col 4:12 (v. Lft., in l.).
3. to fill: Ro 15:13, L, mg. (Cl. Ro., I Co 54); metaph., pass., to be filled with, hence, fully bent on (Ec 8:11).†

Abbott-Smith References

Book Refs
Ecclesiastes 8:11
Luke 1:1
Romans 4:21 · 14:5 · 15:13
Colossians 4:12
2 Timothy 4:5 · 4:17

Liddell-Scott-Jones

πληροφορέω-έω,

bring full measure: satisfy fully, [Refs 2nd c.AD+]; especially assure, τινὰ ὅρκοις [Refs 5th c.BC+]

__2 fulfil, τὴν διακονίαν [NT+1st c.AD+]:—passive, to be fulfilled, [NT+2nd c.AD+]
__3 pay in full, [Refs 3rd c.AD+]
__II passive, of persons, have full satisfaction, to be fully assured, ὅτι.. [NT]
__II.2 π. τοῦ ποιῆσαι to be fully bent on doing, [LXX]

LSJ Scripture Refs: 2Tim.4.5Luke.1.1Rom.4.21LXX.Eccl.8.11