if only

Short definition from Wiktionary

Conjunction

1. 1
   Used other than figuratively or idiomatically: see if, only.
2. 2
   I wish that; would (that) (archaic). Signifies a wish or desire for the present or the future.
3. 3
   I wish that; would (that) (archaic). Signifies a regret about an action in the past.
4. 4
   Even if for no other reason than; only just.
5. 5
   Signifies a hypothetical or wishful precondition, or one which would be simple but is nonetheless unlikely, for a hypothetical, counterfactual, or future outcome.