From phuo; growth (by germination or expansion), i.e. (by implication) natural production (lineal descent); by extension, a genus or sort; figuratively, native disposition, constitution or usage -- (man-)kind, nature(-al).
see GREEK phuo
a. the nature of things, the force, laws, order, of nature; as opposed to what is monstrous, abnormal, perverse: ὁ, ἡ, τό παρά φύσιν, that which is contrary to nature's laws, against nature, Romans 1:26 (οἱ παρά φύσιν τῇ Ἀφροδιτη χρώμενοι, Athen. 13, p. 605; ὁ παιδεραστής ... τήν παρά φύσιν ἡδονήν διώκει, Philo de spec. legg. i., § 7); as opposed to what has been produced by the art of man: οἱ κατά φύσιν κλάδοι, the natural branches, i. e. branches by the operation of nature, Romans 11:21, 24 (Winer's Grammar, 193 (182)), contrasted with οἱ ἐγκεντρισθεντες παρά φύσιν, contrary to the plan of nature, cf. 24; ἡ κατά φύσιν ἀγριέλαιος, ibid.; as opposed to what is imaginary or fictitious: οἱ μή φύσει ὄντες θεοί, who are gods not by nature, but according to the mistaken opinion of the Gentiles (λεγόμενοι θεοί, 1 Corinthians 8:5), Galatians 4:8; nature, i. e. natural sense, native conviction or knowledge, as opposed to what is learned by instruction and accomplished by training or prescribed by law: ἡ φύσις (i. e. the native sense of propriety) διδάσκει τί, 1 Corinthians 11:14; φύσει ποιεῖν τά τοῦ ναμου, natura magistra, guided by their natural sense of what is right and proper, Romans 2:14.
b. birth, physical origin: ἡμεῖς φύσει Ἰουδαῖοι, we so far as our origin is considered, i. e. by birth, are Jews, Galatians 2:15 (φύσει νεώτερος, Sophocles O. C. 1295; τῷ μέν φύσει πατρίς, τόν δέ νόμῳ πολίτην ἐπεποιηντο, Isocrates Evagr. 21; φύσει βάρβαροι ὄντες, νόμῳ δέ Ἕλληνες, Plato, Menex., p. 245 d.; cf. Grimm on Wis. 13:1); ἡ ἐκ φύσεως ἀκροβυστία, who by birth is uncircumcised or a Gentile (opposed to one who, although circumcised, has made himself a Gentile by his iniquity and spiritual perversity), Romans 2:27.
c. a mode of feeling and acting which by long habit has become nature: ἦμεν φύσει τέκνα ὀργῆς, by (our depraved) nature we were exposed to the wrath of God, Ephesians 2:3 (this meaning is evident from the preceding context, and stands in contrast with the change of heart and life wrought through Christ by the blessing of divine grace; φύσει πρός τάς κολασεις ἐπιεικῶς ἔχουσιν οἱ Φαρισαῖοι, Josephus, Antiquities 13, 10, 6. (Others (see Meyer) would lay more stress here upon the constitution in which this 'habitual course of evil' has its origin, whether that constitution be regarded (with some) as already developed at birth, or (better) as undeveloped; cf. Aristotle, pol. 1, 2, p. 1252{b}, 32f οἷον ἕκαστον ἐστι τῆς γενέσεως τελεσθεισης, ταύτην φαμέν τήν φύσιν εἶναι ἑκάστου, ὥσπερ ἀνθρώπου, etc.; see the examples in Bonitz's index under the word. Cf. Winers Grammar, § 31, 6a.)).
d. the sum of innate properties and powers by which one person differs from others, distinctive native peculiarities, natural characteristics: φύσις θηρίων (the natural strength, ferocity and intractability of beasts (A. V. (every) kind of beasts)), ἡ φύσις ἡ ἀνθρωπίνῃ (the ability, art, skill, of men, the qualities which are proper to their nature and necessarily emanate from it), James 3:7 (cf. Winer's Grammar, § 31, 10); θείας κοινωνοί φύσεως, (the holiness distinctive of the divine nature is specially referred to), 2 Peter 1:4 (Ἀμενωφει ... θείας δοκουντι μετεσχηκεναι φύσεως κατά τέ σοφίαν καί πρόγνωσιν τῶν, ἐσομενων, Josephus, contra Apion 1, 26).