Synonyms of investigations

1 Syllable
pike, search, quiz, quest, case
2 Syllables
probing, sounding, surveying, research, probe, gander, hearing, hustle, survey, review, inquest, legwork, study, delving
3 Syllables
observing, fact-finding, inquiry, scrutiny, inspection
4 Syllables
inquisition, analysis, observation, exploration
5 Syllables
examination