Usage: 7 forms in 15 verses
Form Translated As     In Verse(s)
μοχθώ make an effort LXX.Eccl.4.8
μοχθείσ made an effort LXX.Eccl.9.9
μοχθεί he is troubled LXX.Eccl.1.3
he makes an effort LXX.Eccl.5.16
makes an effort LXX.Eccl.2.22LXX.Eccl.3.9
μοχθήση he should make an effort in LXX.Eccl.5.18
should make an effort LXX.Eccl.8.17
εμόχθησεν make an effort LXX.Eccl.2.21
troubled LXX.Lam.3.5
εμόχθησασ you troubled LXX.Isa.62.8
εμόχθησα I made an effort LXX.Eccl.2.11LXX.Eccl.2.20
I made an effort in LXX.Eccl.2.19
made an effort LXX.Eccl.2.18

Liddell-Scott-Jones

μοχθέω (mochtheō) to make an effort G:V

μοχθέω-έω,

to be weary or worn with toil, to be sore distressed, ἀλλά μιν οἴω κήδεσι μοχθέωήσειν [Refs 8th c.BC+]; χείμωνι μόχθεντες (probably) μεγάλῳ μάλα [Refs 7th c.BC+]: absolutely, work hard, labour, κάματός ἐστι τοῖς αὐτοῖς μοχθέωεῖν καὶ ἄρχεσθαι [Refs 5th c.BC+]; ἐπὶ χρηστοῖς (i.e. τέκνοις) [Refs] undergo hardships, [Refs]; execute painful tasks, μ. πόνους [μοχθέωησάτην 5th-6th c.BC: Xenophon Historicus “Anabasis” 6.6.31 ">Refs 5th c.BC+]; τάδε, ταῦτα μ., [Refs 5th c.BC+]; μαθήματα μ. toil at learning, [Refs 5th c.BC+]

__2 with accusative objecti, τέκνα.. ἁμόχθησα the children over whom I toiled, [Refs 5th c.BC+]; μ. πόδα σὸν θεραπεύμασιν, ={θεραπεύειν}, [Refs] —Cf.μόχθος.