| in strict confidence(expression, idiom, quietly, secretly, personally) |
| in unison(expression, together, jointly, collectively, accordingly) |
| inextricably(together, jointly, collectively, accordingly, harmoniously) |
| inly |
| insidiously(quietly, secretly, personally, privately, furtively) |
| intently(adverb, hard, thoroughly, closely, carefully) |
| internal |
| like-mindedly(adverb, amiably) |
| lovingly(adverb, lovingly) |
| meticulously(adverb, hard, thoroughly, closely, carefully) |
| mindfully(adverb, hard, thoroughly, closely, carefully) |
| minutely(adverb, hard, thoroughly, closely, carefully) |
| most |
| mutually(together, jointly, collectively, accordingly, harmoniously) |
| narrowly(adverb, thoroughly, carefully, faithfully) |
| necessarily |
| nigh |
| obscurely(quietly, secretly, personally, privately, furtively) |
| on the QT(expression, idiom, quietly, secretly, personally) |
| on the quiet(expression, idiom, quietly, secretly, personally) |