Lexical Definition

‎ἀντιπίπτω‎ antipíptō (an-tee-pip'-to) to resist ^G:V
from ‎ἀντί‎ and ‎πίπτω‎ (including its alternate)

resist.

• to oppose

Abbott-Smith

ἀντι-πίπτω, [in LXX: Ex 26:5 (קבל), Ex 26:17 (שׁלב), Nu 27:14 (מְרִיבָה), Jb 23:13 (שׁוּב hi.)*;]
1. to fall against or upon (Arist., Polyb.).
2. to strive against, resist (Arist.): c. dat., Ac 7:51.

Abbott-Smith References

Liddell-Scott-Jones

ἀντιπίπτω,

collide, [Refs 4th c.BC+]; fall upon, ταῖς σπείραις[Refs 2nd c.BC+]

__2 resist, ἀντιπῖπτον resisting body, [NT+4th c.BC+]; μηδὲν ἀντιπεσόντα without demur, [Refs 2nd c.BC+]; τῆς φράσεως οὐκ -ούσης[Refs 2nd c.AD+]; ἀντιπῖπτον an objection, [Refs 6th c.AD+]
__3 of circumstances, to be adverse, τινί[Refs 2nd c.BC+]; of contrary winds, [Refs]; tell against, conflict with (fact or theory), [Refs 1st c.BC+]
__II to fall in a contrary direction, αἱ σκιαί[Refs 1st c.BC+]

_{LSJ Scripture Refs: Acts.7.51}