Quick Definition
inward thought, reflection, thoughts
Strong's Definition
deliberation
Derivation: from G1760 (ἐνθυμέομαι);
KJV Usage: device, thought
Thayer's Greek Lexicon
ἐνθύμησις, ἐνθυμήσεως, ἡ, a thinking, consideration: Act_17:29 (A. V. device); plural thoughts: Mat_9:4; Mat_12:25; Heb_4:12 (here L marginal reading singular). (Rare in the classics; Hippocrates, Euripides, Thucydides, Lucian.)
Mounce Concise Greek Dictionary
ἐνθύμησις enthumēsis 4x
the act of thought, reflection, Mat_9:4 ; Mat_12:25 ; Heb_4:12 ;
the result of thought, invention, device, Act_17:29
Abbott-Smith Greek Lexicon
** ἐμθύμησις , -εως , ἡ
( < ἐνθυμέομαι ),
[in Sm .: Job_21:27 , Eze_11:21 * ;]
consideration, pondering ( EV , device ): Act_17:29 ; pl ., thoughts, feel\-ings: Mat_9:4 ; Mat_12:25 , Heb_4:12 .†
SYN.: ἔννοια G1771 , the action of the reason; while ἐνθ . is rather that of the affections ( cf. Westc ., Heb ., l.c .).
Moulton & Milligan — Vocabulary of the Greek NT
ἐνθύμησις [page 215]
P Lond 46 .328 (iv/A.D.) (= I. p. 75) καταδεσμεύω δὲ αὐτοῦ τὸν νοῦν καὶ τὰς φρένας τὴν ἐνθύμησιν τὰς πράξεις ὅπως κτλ . a magic charm; BGU IV. 1024 iv. 12 (iv/v A.D.) ποίας δὲ ἔσχεν ἐνθυμήσεις τὸν ἤδη κληθέντα καὶ τῆς ἐσχάτης ἐλπίδας ( l. ος ) ἀποστε [ρ ]ῆσαι ; Vett. Val. p. 301 .3 τὸ ἐξελέγξαι ἀλλοτρίας ἐνθυμήσεις μυστικῶς κατακεχωσμένας .
Liddell-Scott — Intermediate Greek Lexicon
ἐνθύμησις [Etym: from ἐνθυμέομαι] "consideration, esteem", Thuc.
STEPBible — Tyndale Abridged Greek Lexicon
ἐνθύμησις, -εως, ἡ
(ἐνθυμέομαι), [in Sm.: Job.21:27, Eze.11:21 * ;]
consideration, pondering (EV, device): Act.17:29; pl., thoughts, feelings: Mat.9:4 12:25, Heb.4:12.†
SYN.: ἔννοια, the action of the reason; while ἐνθ. is rather that of the affections (cf. Westc., Heb., l.with) (AS)