The word is used by Paul here:
NIV 1 Corinthians 11:
27 So then, whoever eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of sinning against the body and blood of the Lord. 28 Everyone ought to examine themselves before they eat of the bread and drink from the cup. 29 For those who eat and drink without discerning the body of Christ eat and drink judgment on themselves. 30 That is why many among you are weak and sick, and a number of you have fallen asleep. 31 But if we were more discerning with regard to ourselves, we would not come under such judgment. 32 Nevertheless, when we are judged in this way by the Lord, we are being disciplined so that we will not be finally condemned with the world.
The word I'm concerned about is in verse 29, which I've highlighted:
SBLGNT 1 Corinthians 11:29 ὁ γὰρ ἐσθίων καὶ [u]πίνων κρίμα ἑαυτῷ ἐσθίει καὶ πίνει μὴ διακρίνων τὸ [v]σῶμα.
The word has a wide semantic domain:
**διακρίνω** fut. διακρινῶ; 1 aor. διέκρινα LXX; impf. mid. διεκρινόμην. Pass.: fut. διακριθήσομαι LXX; 1 aor. διεκρίθην (s. κρίνω, διάκρισις; Hom.+).
① to differentiate by separating, separate, arrange (Jos., Ant. 11, 56; Ath. 13, 2; 22, 1; Mel. P. 82, 611) of created things πάντα κατὰ τάξιν δ. effect an orderly arrangement for everything Dg 8:7. ἑαυτὸν δ. separate oneself IEph 5:3 (but the ominous tone of the context favors 3b below).
② to conclude that there is a difference, make a distinction, differentiate (PGM 5, 103f σὺ διέκρινας τὸ δίκαιον καὶ τὸ ἄδικον; 4 Macc 1:14; Jos., Bell. 1, 27; Just., D. 20, 3; Ath. 15, 1) μεταξὺ ἡμῶν τε καὶ αὐτῶν betw. us and them Ac 15:9. τίς σε διακρίνει; who concedes you any superiority? 1 Cor 4:7 (Appian, Bell. Civ. 5, 54 §228 δ. τινά=concede superiority to someone, beside ἐπιλέγεσθαί τινα=select someone; cp. Philo, Op. M. 137 διακρίνας ἐξ ἁπάσης τὸ βέλτιστον). μηθὲν διακρίνων τίνι δῷ without distinguishing to whom he should give Hm 2:6; cp. Ac 11:12.—Pass. διακρίνεσθαί τινος be differentiated fr. someone Dg 5:1.
③ to evaluate by paying careful attention to, evaluate, judge
ⓐ judge correctly (Job 12:11; 23:10) the appearance of the sky Mt 16:3; evaluate oneself 1 Cor 11:31; recognize τὸ σῶμα vs. 29.
ⓑ pass judgment on w. acc. ἑαυτόν on oneself IEph 5:3 (mng. 1 is also prob.); προφήτην D 11:7; abs. 1 Cor 14:29.
④ to render a legal decision, judge, decide, legal t.t. (X., Hell. 5, 2, 10; Appian, Bell. Civ. 5, 76 §324 δίκαι διεκρίνοντο; SIG 545, 18; OGI 43, 4 and11; pap; EpArist 110; Just. A II, 7, 2) ἀνὰ μέσον τινός decide betw. pers. (as Ezk 34:17, 20) 1 Cor 6:5; s. EvDobschütz, StKr 91, 1918, 410–21 and ἀνά 1b, μέσος 1b.
⑤ to be at variance w. someone, mid., w. pass. aor. (B-D-F. §78)
ⓐ because of differing judgments dispute τινί w. someone (Polyb. 2, 22, 11) Jd 9.
ⓑ by maintaining a firm opposing position or adverse judgment take issue πρός τινα w. someone (Hdt. 9, 58, 2; Ezk 20:35f; Jo 4:2) Ac 11:2 (=criticize).
⑥ to be uncertain, be at odds w. oneself, doubt, waver (this mng. appears first in NT; with no dependence on the NT, e.g., Cyril of Scyth. p. 52, 17; 80, 10; 174, 7) Mt 21:21; Mk 11:23; Ro 14:23; Jd 22. ἐν ἑαυτῷ in one’s own mind Lk 11:38 D; Js 2:4; GJs 11:2. W. εἰς Ro 4:20 μηδὲν διακρινόμενος without any doubting Js 1:6; hesitate Ac 10:20.—DELG s.v. κρίνω. M-M. TW.
Arndt, W., Danker, F. W., Bauer, W., & Gingrich, F. W. (2000). A Greek-English lexicon of the New Testament and other early Christian literature (3rd ed., p. 231). Chicago: University of Chicago Press.
In which sense is Paul using the word here?
The NIV renders this as "discerning" but that isn't provided by BDAG as a common usage of the word and to my mind communicates nothing. Is there a better rendering?