ψεῦδος, -εος (-ους), τό [in LXX chiefly for שֶׁקֶר, also for כַּחַשׁ, כָּזָב ;] a falsehood, untruth, lie: Rev.14:15; opp. to ἡ ἀλήθεια, Refs Jhn.8:44, Rom.1:25, Eph.4:25, 2Th.2:11, 1Jn.2:21; to τὸ ἀληθές, 1Jn.2:27; ποιεῖν ψ., Refs Rev.21:27 22:15; ἐν πάσῃ δυνάμει κ. σημείοις κ. τέρασιν ψεύδους (genitive qual., see M, Th., 104; and on the meaning and construction, see also ICC, in l), 2Th.2:9.† (AS)
Thayer:
1) a lie 2) conscious and intentional falsehood 3) in a broad sense, whatever is not what it seems to be 3a) of perverse, impious, deceitful precepts
ψεῦδος
pseudos
psyoo'-dos
From G5574; a falsehood
ψεύδομαι
pseudomai
psyoo'-dom-ahee
Middle voice of an apparently primary verb; to utteranuntruth or attempt to deceive by falsehood
KJV Usage: falsely, lie.
G5571 ψευδήςψευδής
pseudēs
psyoo-dace'
From G5574; untrue, that is, erroneous, deceitful, wicked
KJV Usage: false, liar.
G5582 ψεῦσμαψεῦσμα
pseusma
psyoos'-mah
From G5574; a fabrication, that is, falsehood
KJV Usage: lie.
G5583 ψεύστηςψεύστης
pseustēs
psyoos-tace'
From G5574; a falsifier
KJV Usage: liar.
G5587 ψιθυρισμόςψιθυρισμός
psithurismos
psith-oo-ris-mos'
From a derivative of ψίθος psithos (a whisper; by implication a slander; probably akin to G5574); whispering, that is, secret detraction