130 entries under investigate topic. ×

2
assay(verb, study, check, consider, criticize)
2
case(verb, study, check, consider, observe)
2
cast about(verb, expression, check, examine, look)
2
check out(verb, expression, study, check, consider)
2
check over(verb, expression, study, check, run)
2
check up(expression, study, consider, examine, review)
2
chew over(expression, study, check, consider, criticize)
2
eye(verb, study, check, consider, criticize)
2
feel out(expression, study, consider, examine, review)
2
finger(verb, study, place, part, check)
2
frisk(verb, study, check, consider, observe)
2
go over with a fine-tooth comb(expression, idiom, study, check, consider)
2
grope(verb, check, examine, look, seek)
2
grub(verb, check, turn, produce, clean)
2
gun(verb, study, check, consider, criticize)
2
hunt(verb, check, examine, try, discover)
2
interrogate(verb, study, check, consider, examine)
2
leave no stone unturned(verb, expression, idiom, action, check)
2
look-see(verb, study, consider, examine, review)
2
look high and low(verb, expression, idiom, check, examine)
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APASmart Define. (2016). sift thesaurus. Retrieved September 29, 2026, from https://smartdefine.org/sift/thesaurus/synonyms
ChicagoSmart Define. 2016. "sift thesaurus" https://smartdefine.org/sift/thesaurus/synonyms (accessed September 29, 2026).
HarvardSmart Define 2016, sift thesaurus, Smart Define, viewed 29 September, 2026, <https://smartdefine.org/sift/thesaurus/synonyms>.
MLASmart Define. "sift thesaurus" 29 March 2016. Web. 29 September 2026. <https://smartdefine.org/sift/thesaurus/synonyms>