ὑφίστημι fut. ὑποστήσω aor1 ὑπέστησα in these tenses Causal, to place or set under, τί τινι Hdt., Pind.; τρεῖς σταυροὺς ὑπίστησι plants three piles in the lake to support a house, Hdt.:—metaph., γνώμας ὑποστήσας σοφάς having laid them as a foundation, Soph. to post secretly or in ambush, Hdt., Xen. Causal also in fut. and aor1 mid. to substitute, τί τινι one thing for another, Xen. Pass., with aor2 act. ὑπ-έστην, perf. ὑφ-έστηκα, Ionic part. ὑπ-εστεώς:— to stand under as a support, c. dat., Hdt. to sink to the bottom, settle, τὸ ὑφιστάμενον the milk, opp. to τὸ ἐφιστάμενον (the cream), Hdt. to place oneself under an engagement, engage or promise to do, c. inf. fut., ὅσσʼ Ἀχιλῆι ὑπέστημεν δώσειν Il., etc.; c. inf. aor., οὔ τίς με ὑπέστη σαῶσαι Il.; c. inf. pres., Hdt.:—absol., after promise given, Od.; ὥσπερ ὑπέστη as he promised, Thuc.:—when foll. by acc., an inf. may be supplied, τρίποδας οὕς οἱ ὑπέστη (sc. δώσειν) Il.; ἐκτελέουσιν ὑπόσχεσιν ἥνπερ ὑπέσταν Il. to submit to any one, τινι Il. c. acc. rei, to submit to, consent to, ὁ τὸ ἐλάχιστον ὑπιστάμενος who offers to take the least, Hdt.; ὑφ. τὸν πλοῦν to undertake it unwillingly, Thuc.; so, ὑφ. τὸν κίνδυνον Thuc.: —rarely c. dat., ὑφ. ξυμφοραῖς ταῖς μεγίσταις Thuc. to undertake an office, Xen. to lie concealed or in ambush, Hdt., Eur., etc. to support an attack, to resist, withstand, c. dat., Aesch.; c. acc., Eur., Thuc.:—absol. to stand oneʼs ground, face the enemy, Lat. subsistere, Eur., Thuc.